

GSTREAMER 1.16 RELEASE NOTES


GStreamer 1.16 has not been released yet. It is scheduled for release in
April 2019.

1.15.x is the unstable development version that is being developed in
the git master branch and which will eventually result in 1.16.

1.16 will be backwards-compatible to the stable 1.14, 1.12, 1.10, 1.8,
1.6, 1.4, 1.2 and 1.0 release series.

See https://gstreamer.freedesktop.org/releases/1.16/ for the latest
version of this document.

_Last updated: Wednesday 10 April 2019, 00:50 UTC (log)_


Introduction

The GStreamer team is proud to announce a new major feature release in
the stable 1.x API series of your favourite cross-platform multimedia
framework!

As always, this release is again packed with many new features, bug
fixes and other improvements.


Highlights

-   GStreamer WebRTC stack gained support for data channels for
    peer-to-peer communication based on SCTP, BUNDLE support, as well as
    support for multiple TURN servers.

-   AV1 video codec support for Matroska and QuickTime/MP4 containers
    and more configuration options and supported input formats for the
    AOMedia AV1 encoder

-   Support for Closed Captions and other Ancillary Data in video

-   Support for planar (non-interleaved) raw audio

-   GstVideoAggregator, compositor and OpenGL mixer elements are now in
    -base

-   New alternate fields interlace mode where each buffer carries a
    single field

-   WebM and Matroska ContentEncryption support in the Matroska demuxer

-   new WebKit WPE-based web browser source element

-   Video4Linux: HEVC encoding and decoding, JPEG encoding, and improved
    dmabuf import/export

-   Hardware-accelerated Nvidia video decoder gained support for VP8/VP9
    decoding, whilst the encoder gained support for H.265/HEVC encoding.

-   Many improvements to the Intel Media SDK based hardware-accelerated
    video decoder and encoder plugin (msdk): dmabuf import/export for
    zero-copy integration with other components; VP9 decoding; 10-bit
    HEVC encoding; video post-processing (vpp) support including
    deinterlacing; and the video decoder now handles dynamic resolution
    changes.

-   The ASS/SSA subtitle overlay renderer can now handle multiple
    subtitles that overlap in time and will show them on screen
    simultaneously

-   The Meson build is now feature-complete (*) and it is now the
    recommended build system on all platforms. The Autotools build is
    scheduled to be removed in the next cycle.

-   The GStreamer Rust bindings and Rust plugins module are now
    officially part of upstream GStreamer.

-   Many performance improvements


Major new features and changes

Noteworthy new API

-   GstAggregator has a new "min-upstream-latency" property that forces
    a minimum aggregate latency for the input branches of an aggregator.
    This is useful for dynamic pipelines where branches with a higher
    latency might be added later after the pipeline is already up and
    running and where a change in the latency would be disruptive. This
    only applies to the case where at least one of the input branches is
    live though, it won’t force the aggregator into live mode in the
    absence of any live inputs.

-   GstBaseSink gained a "processing-deadline" property and
    setter/getter API to configure a processing deadline for live
    pipelines. The processing deadline is the acceptable amount of time
    to process the media in a live pipeline before it reaches the sink.
    This is on top of the systemic latency that is normally reported by
    the latency query. This defaults to 20ms and should make pipelines
    such as v4l2src ! xvimagesink not claim that all frames are late in
    the QoS events. Ideally, this should replace the "max-lateness"
    property for most applications.

-   RTCP Extended Reports (XR) parsing according to RFC 3611:
    Loss/Duplicate RLE, Packet Receipt Times, Receiver Reference Time,
    Delay since the last Receiver (DLRR), Statistics Summary, and VoIP
    Metrics reports. This only provides the ability to parse such
    packets, generation of XR packets is not supported yet and XR
    packets are not automatically parsed by rtpbin / rtpsession but must
    be actively handled by the application.

-   a new mode for interlaced video was added where each buffer carries
    a single field of interlaced video, with buffer flags indicating
    whether the field is the top field or bottom field. Top and bottom
    fields are expected to alternate in this mode. Caps for this
    interlace mode must also carry a format:Interlaced caps feature to
    ensure backwards compatibility.

-   The video library has gained support for three new raw pixel
    formats:

    -   Y410: packed 4:4:4 YUV, 10 bits per channel
    -   Y210: packed 4:2:2 YUV, 10 bits per channel
    -   NV12_10LE40: fully-packed 10-bit variant of NV12_10LE32,
        i.e. without the padding bits

-   GstRTPSourceMeta is a new meta that can be used to transport
    information about the origin of depayloaded or decoded RTP buffers,
    e.g. when mixing audio from multiple sources into a single stream. A
    new "source-info" property on the RTP depayloader base class
    determines whether depayloaders should put this meta on outgoing
    buffers. Similarly, the same property on RTP payloaders determines
    whether they should use the information from this meta to construct
    the CSRCs list on outgoing RTP buffers.

-   gst_sdp_message_from_text() is a convenience constructor to parse
    SDPs from a string which is particularly useful for language
    bindings.

Support for Planar (Non-Interleaved) Raw Audio

Raw audio samples are usually passed around in interleaved form in
GStreamer, which means that if there are multiple audio channels the
samples for each channel are interleaved in memory, e.g.
|LEFT|RIGHT|LEFT|RIGHT|LEFT|RIGHT| for stereo audio. A non-interleaved
or planar arrangement in memory would look like
|LEFT|LEFT|LEFT|RIGHT|RIGHT|RIGHT| instead, possibly with
|LEFT|LEFT|LEFT| and |RIGHT|RIGHT|RIGHT| residing in separate memory
chunks or separated by some padding.

GStreamer has always had signalling for non-interleaved audio since
version 1.0, but it was never actually properly implemented in any
elements. audioconvert would advertise support for it, but wasn’t
actually able to handle it correctly.

With this release we now have full support for non-interleaved audio as
well, which means more efficient integration with external APIs that
handle audio this way, but also more efficient processing of certain
operations like interleaving multiple 1-channel streams into a
multi-channel stream which can be done without memory copies now.

New API to support this has been added to the GStreamer Audio support
library: There is now a new GstAudioMeta which describes how data is
laid out inside the buffer, and buffers with non-interleaved audio must
always carry this meta. To access the non-interleaved audio samples you
must map such buffers with gst_audio_buffer_map() which works much like
gst_buffer_map() or gst_video_frame_map() in that it will populate a
little GstAudioBuffer helper structure passed to it with the number of
samples, the number of planes and pointers to the start of each plane in
memory. This function can also be used to map interleaved audio buffers
in which case there will be only one plane of interleaved samples.

Of course support for this has also been implemented in the various
audio helper and conversion APIs, base classes, and in elements such as
audioconvert, audioresample, audiotestsrc, audiorate.

Support for Closed Captions and Other Ancillary Data in Video

The video support library has gained support for detecting and
extracting Ancillary Data from videos as per the SMPTE S291M
specification, including:

-   a VBI (Vertical Blanking Interval) parser that can detect and
    extract Ancillary Data from Vertical Blanking Interval lines of
    component signals. This is currently supported for videos in v210
    and UYVY format.

-   a new GstMeta for closed captions: GstVideoCaptionMeta. This
    supports the two types of closed captions, CEA-608 and CEA-708,
    along with the four different ways they can be transported (other
    systems are a superset of those).

-   a VBI (Vertical Blanking Interval) encoder for writing ancillary
    data to the Vertical Blanking Interval lines of component signals.

The new closedcaption plugin in gst-plugins-bad then makes use of all
this new infrastructure and provides the following elements:

-   cccombiner: a closed caption combiner that takes a closed captions
    stream and another stream and adds the closed captions as
    GstVideoCaptionMeta to the buffers of the other stream.

-   ccextractor: a closed caption extractor which will take
    GstVideoCaptionMeta from input buffers and output them as a separate
    closed captions stream.

-   ccconverter: a closed caption converter that can convert between
    different formats

-   line21decoder: extract line21 closed captions from SD video streams

-   cc708overlay: decodes CEA 608/708 captions and overlays them on
    video

Additionally, the following elements have also gained Closed Caption
support:

-   qtdemux and qtmux support CEA 608/708 Closed Caption tracks

-   mpegvideoparse extracts Closed Captions from MPEG-2 video streams

-   decklinkvideosink can output closed captions and decklinkvideosrc
    can extract closed captions

-   playbin and playbin3 learned how to autoplug CEA 608/708 CC overlay
    elements

-   the externally maintained ajavideosrc element for AJA capture cards
    has support for extracting closed captions

The rsclosedcaption plugin in the Rust plugins collection includes a
MacCaption (MCC) file parser and encoder.

New Elements

-   overlaycomposition: New element that allows applications to draw
    GstVideoOverlayCompositions on a stream. The element will emit the
    "draw" signal for each video buffer, and the application then
    generates an overlay for that frame (or not). This is much more
    performant than e.g. cairooverlay for many use cases, e.g. because
    pixel format conversions can be avoided or the blitting of the
    overlay can be delegated to downstream elements (such as
    gloverlaycompositor). It’s particularly useful for cases where only
    a small section of the video frame should be drawn on.

-   gloverlaycompositor: New OpenGL-based compositor element that
    flattens any overlays from GstVideoOverlayCompositionMetas into the
    video stream. This element is also always part of glimagesink.

-   glalpha: New element that adds an alpha channel to a video stream.
    The values of the alpha channel can either be set to a constant or
    can be dynamically calculated via chroma keying. It is similar to
    the existing alpha element but based on OpenGL. Calculations are
    done in floating point so results may not be identical to the output
    of the existing alpha element.

-   rtpfunnel funnels together RTP streams into a single session. Use
    cases include multiplexing and bundle. webrtcbin uses it to
    implement BUNDLE support.

-   testsrcbin is a source element that provides an audio and/or video
    stream and also announces them using the recently-introduced
    GstStream API. This is useful for testing elements such as playbin3
    or uridecodebin3 etc.

-   New closed caption elements: cccombiner, ccextractor, ccconverter,
    line21decoder and cc708overlay (see above)

-   wpesrc: new source element acting as a Web Browser based on WebKit
    WPE

-   Two new OpenCV-based elements: cameracalibrate and cameraundistort
    that can communicate to figure out distortion correction parameters
    for a camera and correct for the distortion.

-   New sctp plugin based on usrsctp with sctpenc and sctpdec elements.
    These elements are used inside webrtcbin for implementing data
    channels.

New element features and additions

-   playbin3, playbin and playsink have gained a new "text-offset"
    property to adjust the positioning of the selected subtitle stream
    vis-a-vis the audio and video streams. This uses subtitleoverlay’s
    new "subtitle-ts-offset" property. GstPlayer has gained matching API
    for this, namely gst_player_get_text_video_offset().

-   playbin3 buffering improvements: in network playback scenarios there
    may be multiple inputs to decodebin3, and buffering will be done
    before decodebin3 using queue2 or downloadbuffer elements inside
    urisourcebin. Since this is before any parsers or demuxers there may
    not be any bitrate information available for the various streams, so
    it was difficult to configure the buffering there smartly within
    global constraints. This was improved now: The queue2 elements
    inside urisourcebin will now use the new bitrate query to figure out
    a bitrate estimate for the stream if no bitrate was provided by
    upstream, and urisourcebin will use the bitrates of the individual
    queues to distribute the globally-set "buffer-size" budget in bytes
    to the various queues. urisourcebin also gained "low-watermark" and
    "high-watermark" properties which will be proxied to the internal
    queues, as well as a read-only "statistics" property which allows
    querying of the minimum/maximum/average byte and time levels of the
    queues inside the urisourcebin in question.

-   splitmuxsink has gained a couple of new features:

    -   new "async-finalize" mode: This mode is useful for muxers or
        outputs that can take a long time to finalize a file. Instead of
        blocking the whole upstream pipeline while the muxer is doing
        its stuff, we can unlink it and spawn a new muxer + sink
        combination to continue running normally. This requires us to
        receive the muxer and sink (if needed) as factories via the new
        "muxer-factory" and "sink-factory" properties, optionally
        accompanied by their respective properties structures (set via
        the new "muxer-properties" and "sink-properties" properties).
        There are also new "muxer-added" and "sink-added" signals in
        case custom code has to be called for them to configure them.

    -   "split-at-running-time" action signal: When called by the user,
        this action signal ends the current file (and starts a new one)
        as soon as the given running time is reached. If called multiple
        times, running times are queued up and processed in the order
        they were given.

    -   "split-after" action signal to finish outputting the current GOP
        to the current file and then start a new file as soon as the GOP
        is finished and a new GOP is opened (unlike the existing
        "split-now" which immediately finishes the current file and
        writes the current GOP into the next newly-started file).

    -   "reset-muxer" property: when unset, the muxer is reset using
        flush events instead of setting its state to NULL and back. This
        means the muxer can keep state across resets, e.g. mpegtsmux
        will keep the continuity counter continuous across segments as
        required by hlssink2.

-   qtdemux gained PIFF track encryption box support in addition to the
    already-existing PIFF sample encryption support, and also allows
    applications to select which encryption system to use via a
    "drm-preferred-decryption-system-id" context in case there are
    multiple options.

-   qtmux: the "start-gap-threshold" property determines now whether an
    edit list will be created to account for small gaps or offsets at
    the beginning of a stream in case the start timestamps of tracks
    don’t line up perfectly. Previously the threshold was hard-coded to
    1% of the (video) frame duration, now it is 0 by default (so edit
    list will be created even for small differences), but fully
    configurable.

-   rtpjitterbuffer has improved end-of-stream handling

-   rtpmp4vpay will be prefered over rtpmp4gpay for MPEG-4 video in
    autoplugging scenarios now

-   rtspsrc now allows applications to send RTSP SET_PARAMETER and
    GET_PARAMETER requests using action signals.

-   rtspsrc has a small (100ms) configurable teardown delay by default
    to try and make sure an RTSP TEARDOWN request gets sent out when the
    source element shuts down. This will block the downward PAUSED to
    READY state change for a short time, but can be disabled where it’s
    a problem. Some servers only allow a limited number of concurrent
    clients, so if no proper TEARDOWN is sent new clients may have
    problems connecting to the server for a while.

-   souphttpsrc behaves better with low bitrate streams now. Before it
    would increase the read block size too quickly which could lead to
    it not reading any data from the socket for a very long time with
    low bitrate streams that are output live downstream. This could lead
    to servers kicking off the client.

-   filesink: do internal buffering to avoid performance regression with
    small writes since we bypass libc buffering by using writev()
    instead of fwrite()

-   identity: add "eos-after" property and fix "error-after" property
    when the element is reused

-   input-selector: lets context queries pass through, so that
    e.g. upstream OpenGL elements can use contexts and displays
    advertised by downstream elements

-   queue2: avoid ping-pong between 0% and 100% buffering messages if
    upstream is pushing buffers larger than one of its limits, plus
    performance optimisations

-   opusdec: new "phase-inversion" property to control phase inversion.
    When enabled, this will slightly increase stereo quality, but
    produces a stream that when downmixed to mono will suffer audio
    distortions.

-   The x265enc HEVC encoder also exposes a "key-int-max" property to
    configure the maximum allowed GOP size now.

-   decklinkvideosink has seen stability improvements for long-running
    pipelines (potential crash due to overflow of leaked clock refcount)
    and clock-slaving improvements when performing flushing seeks
    (causing stalls in the output timeline), pausing and/or buffering.

-   srtpdec, srtpenc: add support for MKIs which allow multiple keys to
    be used with a single SRTP stream

-   The srt Secure Reliable Transport plugin has integrated server and
    client elements srt{client,server}{src,sink} into one (srtsrc and
    srtsink), since SRT connection mode can be changed by uri
    parameters.

-   h264parse and h265parse will handle SEI recovery point messages and
    mark recovery points as keyframes as well (in addition to IDR
    frames)

-   webrtcbin: "add-turn-server" action signal to pass multiple ICE
    relays (TURN servers).

-   The removesilence element has received various new features and
    properties, such as a "threshold" property, detecting silence only
    after minimum silence time/buffers, a "silent" property to control
    bus message notifications as well as a "squash" property.

-   AOMedia AV1 decoder gained support for 10/12bit decoding whilst the
    AV1 encoder supports more image formats and subsamplings now and
    acquired support for rate control and profile related configuration.

-   The Fraunhofer fdkaac plugin can now be built against the 2.0.0
    version API and has improved multichannel support

-   kmssink now supports unpadded 24-bit RGB and can configure mode
    setting from video info, which enables display of multi-planar
    formats such as I420 or NV12 with modesetting. It has also gained a
    number of new properties: The "restore-crtc" property does what it
    says on the tin and is enabled by default. "plane-properties" and
    "connector-properties" can be used to pass custom properties to the
    DRM.

-   waylandsink has a "fullscreen" property now.

Plugin and library moves

-   The stereo element was moved from -bad into the existing audiofx
    plugin in -good. If you get duplicate type registration warnings
    when upgrading, check that you don’t have a stale stereoplugin lying
    about somewhere.

GstVideoAggregator, compositor, and OpenGL mixer elements moved from -bad to -base

GstVideoAggregator is a new base class for raw video mixers and muxers
and is based on GstAggregator. It provides defined-latency mixing of raw
video inputs and ensures that the pipeline won’t stall even if one of
the input streams stops producing data.

As part of the move to stabilise the API there were some last-minute API
changes and clean-ups, but those should mostly affect internal elements.
Most notably, the "ignore-eos" pad property was renamed to
"repeat-after-eos" and the conversion code was moved to a
GstVideoAggregatorConvertPad subclass to avoid code duplication, make
things less awkward for subclasses like the OpenGL-based video mixer,
and make the API more consistent with the audio aggregator API.

It is used by the compositor element, which is a replacement for
‘videomixer’ which did not handle live inputs very well. compositor
should behave much better in that respect and generally behave as one
would expected in most scenarios.

The compositor element has gained support for per-pad blending mode
operators (SOURCE, OVER, ADD) which determines what operator to use for
blending this pad over the previous ones. This can be used to implement
crossfading and the available operators can be extended in the future as
needed.

A number of OpenGL-based video mixer elements (glvideomixer, glmixerbin,
glvideomixerelement, glstereomix, glmosaic) which are built on top of
GstVideoAggregator have also been moved from -bad to -base now. These
elements have been merged into the existing OpenGL plugin, so if you get
duplicate type registration warnings when upgrading, check that you
don’t have a stale openglmixers plugin lying about somewhere.

Plugin removals

The following plugins have been removed from gst-plugins-bad:

-   The experimental daala plugin has been removed, since it’s not so
    useful now that all effort is focused on AV1 instead, and it had to
    be enabled explicitly with --enable-experimental anyway.

-   The spc plugin has been removed. It has been replaced by the gme
    plugin.

-   The acmmp3dec and acmenc plugins for Windows have been removed. ACM
    is an ancient legacy API and there was no point in keeping the
    plugins around for a licensed MP3 decoder now that the MP3 patents
    have expired and we have a decoder in -good. We also didn’t ship
    these in our cerbero-built Windows packages, so it’s unlikely that
    they’ll be missed.


Miscellaneous API additions

-   GstBitwriter: new generic bit writer API to complement the existing
    bit reader

-   gst_buffer_new_wrapped_bytes() creates a wrap buffer from a GBytes

-   gst_caps_set_features_simple() sets a caps feature on all the
    structures of a GstCaps

-   New GST_QUERY_BITRATE query: This allows determining from downstream
    what the expected bitrate of a stream may be which is useful in
    queue2 for setting time based limits when upstream does not provide
    timing information. tsdemux, qtdemux and matroskademux have basic
    support for this query on their sink pads.

-   elements: there is a new “Hardware” class specifier. Elements
    interacting with hardware devices should specify this classifier in
    their element factory class metadata. This is useful to advertise as
    one might need to put such elements into READY state to test if the
    hardware is present in the system for example.

-   protection: Add a new definition for unspecified system protection,
    GST_PROTECTION_UNSPECIFIED_SYSTEM_ID

-   take functions for various mini objects that didn’t have them yet:
    gst_query_take(), gst_message_take(), gst_tag_list_take(),
    gst_buffer_list_take(). Unlike the various _replace() functions
    _take() does not increase the reference count but takes ownership of
    the mini object passed.

-   clear functions for various mini object types and GstObject which
    unrefs the object or mini object (if non-NULL) and sets the variable
    pointed to to NULL: gst_clear_structure(), gst_clear_tag_list(),
    gst_clear_query(), gst_clear_message(), gst_clear_event(),
    gst_clear_caps(), gst_clear_buffer_list(), gst_clear_buffer(),
    gst_clear_mini_object(), gst_clear_object()

-   miniobject: new API gst_mini_object_add_parent() and
    gst_mini_object_remove_parent() to set parent pointers on mini
    objects to ensure correct writability: Every container of
    miniobjects now needs to store itself as parent in the child object,
    and remove itself again later. A mini object is then only writable
    if there is at most one parent, that parent is writable itself, and
    the reference count of the mini object is 1. GstBuffer (for
    memories), GstBufferList (for buffers), GstSample (for caps, buffer,
    bufferlist), and GstVideoOverlayComposition were updated
    accordingly. Without this it was possible to have e.g. a buffer list
    with a refcount of 2 used in two places at once that both modify the
    same buffer with refcount 1 at the same time wrongly thinking it is
    writable even though it’s really not.

-   poll: add API to watch for POLLPRI and stop treating POLLPRI as a
    read. This is useful to wait for video4linux events which are
    signalled via POLLPRI.

-   sample: new API to update the contents of a GstSample and make it
    writable: gst_sample_set_buffer(), gst_sample_set_caps(),
    gst_sample_set_segment(), gst_sample_set_info(), plus
    gst_sample_is_writable() and gst_sample_make_writable(). This makes
    it possible to reuse a sample object and avoid unnecessary memory
    allocations, for example in appsink.

-   ClockIDs now keep a weak reference to underlying clock to avoid
    crashes in basesink in corner cases where a clock goes away while
    the ClockID is still in use, plus some new API
    (gst_clock_id_get_clock(), gst_clock_id_uses_clock()) to check the
    clock a ClockID is linked to.

-   The GstCheck unit test library gained a
    fail_unless_equals_clocktime() convenience macro as well as some new
    GstHarness API for for proposing meta APIs from the allocation
    query: gst_harness_add_propose_allocation_meta(). ASSERT_CRITICAL()
    checks in unit tests are now skipped if GStreamer was compiled with
    GST_DISABLE_GLIB_CHECKS.

-   gst_audio_buffer_truncate() convenience function to truncate a raw
    audio buffer


Miscellaneous performance and memory optimisations

As always there have been many performance and memory usage improvements
across all components and modules. Some of them (such as dmabuf
import/export) have already been mentioned elsewhere so won’t be
repeated here.

The following list is only a small snapshot of some of the more
interesting optimisations that haven’t been mentioned in other contexts
yet:

-   The GstVideoEncoder and GstVideoDecoder base classes now release the
    STREAM_LOCK when pushing out buffers, which means (multi-threaded)
    encoders and decoders can now receive and continue to process input
    buffers whilst waiting for downstream elements in the pipeline to
    process the buffer that was pushed out. This increases throughput
    and reduces processing latency, also and especially for
    hardware-accelerated encoder/decoder elements.

-   GstQueueArray has seen a few API additions
    (gst_queue_array_peek_nth(), gst_queue_array_set_clear_func(),
    gst_queue_array_clear()) so that it can be used in other places like
    GstAdapter instead of a GList, which reduces allocations and
    improves performance.

-   appsink now reuses the sample object in pull_sample() if possible

-   rtpsession only starts the RTCP thread when it’s actually needed now

-   udpsrc uses a buffer pool now and the GstUdpSrc object structure was
    optimised for better cache performance

GstPlayer

-   API was added to fine-tune the synchronisation offset between
    subtitles and video


Miscellaneous changes

-   As a result of moving to newer FFmpeg APIs, encoder and decoder
    elements exposed by the GStreamer FFmpeg wrapper plugin (gst-libav)
    may have seen possibly incompatible changes to property names and/or
    types, and not all properties exposed might be functional. We are
    still reviewing the new properties and aim to minimise breaking
    changes at least for the most commonly-used properties, so please
    report any issues you run into!

OpenGL integration

-   The OpenGL mixer elements have been moved from -bad to
    gst-plugins-base (see above)

-   The Mesa GBM backend now supports headless mode

-   gloverlaycompositor: New OpenGL-based compositor element that
    flattens any overlays from GstVideoOverlayCompositionMetas into the
    video stream.

-   glalpha: New element that adds an alpha channel to a video stream.
    The values of the alpha channel can either be set to a constant or
    can be dynamically calculated via chroma keying. It is similar to
    the existing alpha element but based on OpenGL. Calculations are
    done in floating point so results may not be identical to the output
    of the existing alpha element.

-   glupload: Implement direct dmabuf uploader, the idea being that some
    GPUs (like the Vivante series) can actually perform the YUV->RGB
    conversion internally, so no custom conversion shaders are needed.
    To make use of this feature, we need an additional uploader that can
    import DMABUF FDs and also directly pass the pixel format, relying
    on the GPU to do the conversion.

-   The OpenGL library no longer restores the OpenGL viewport. This is a
    performance optimization to not require performing multiple
    expensive glGet*() function calls per frame. This affects any
    application or plugin use of the following functions and objects:
    -   glcolorconvert library object (not the element)
    -   glviewconvert library object (not the element)
    -   gst_gl_framebuffer_draw_to_texture()
    -   custom GstGLWindow implementations


Tracing framework and debugging improvements

-   There is now a GDB PRETTY PRINTER FOR VARIOUS GSTREAMER TYPES: For
    GstObject pointers the type and name is added, e.g.
    0x5555557e4110 [GstDecodeBin|decodebin0]. For GstMiniObject pointers
    the object type is added, e.g. 0x7fffe001fc50 [GstBuffer]. For
    GstClockTime and GstClockTimeDiff the time is also printed in human
    readable form, e.g. 150116219955 [+0:02:30.116219955].

-   GDB EXTENSION WITH TWO CUSTOM GDB COMMANDS gst-dot AND gst-print:

    -   gst-dot creates dot files that a very close to what
        GST_DEBUG_BIN_TO_DOT_FILE() produces, but object properties and
        buffer contents such as codec-data in caps are not available.

    -   gst-print produces high-level information about a GStreamer
        object. This is currently limited to pads for GstElements and
        events for the pads. The output may look like this:

                    (gdb) gst-print pad.object.parent
                    GstMatroskaDemux (matroskademux0) {
                        SinkPad (sink, pull) {
                        }
                        SrcPad (video_0, push) {
                          events:
                            stream-start:
                              stream-id: 0463ccb080d00b8689bf569a435c4ff84f9ff753545318ae2328ea0763fd0bec/001:1274058367
                            caps: video/x-theora
                              width: 1920
                              height: 800
                              pixel-aspect-ratio: 1/1
                              framerate: 24/1
                              streamheader: < 0x5555557c7d30 [GstBuffer], 0x5555557c7e40 [GstBuffer], 0x7fffe00141d0 [GstBuffer] >
                            segment: time
                              rate: 1
                            tag: global
                              container-format: Matroska
                        }
                        SrcPad (audio_0, push) {
                          events:
                            stream-start:
                              stream-id: 0463ccb080d00b8689bf569a435c4ff84f9ff753545318ae2328ea0763fd0bec/002:1551204875
                            caps: audio/mpeg
                              mpegversion: 4
                              framed: true
                              stream-format: raw
                              codec_data: 0x7fffe0014500 [GstBuffer]
                              level: 2
                              base-profile: lc
                              profile: lc
                              channels: 2
                              rate: 44100
                            segment: time
                              rate: 1
                            tag: global
                              container-format: Matroska
                            tag: stream
                              audio-codec: MPEG-4 AAC audio
                              language-code: en
                        }
                    }

-   gst_structure_to_string() now serialises the actual value of
    pointers when serialising GstStructures instead of claiming they’re
    NULL. This makes debug logging in various places less confusing,
    because it’s clear now that structure fields actually hold valid
    objects. Such object pointer values will never be deserialised
    however.


Tools

-   gst-inspect-1.0 has coloured output now and will automatically use a
    pager if the output does not fit on a page. This only works in a
    UNIX environment and if the output is not piped, and on Windows 10
    build 16257 or newer. If you don’t like the colours you can disable
    them by setting the GST_INSPECT_NO_COLORS=1 environment variable or
    passing the --no-color command line option.


GStreamer RTSP server

-   Improved backlog handling when using TCP interleaved for data
    transport. Before there was a fixed maximum size for backlog
    messages, which was prone to deadlocks and made it difficult to
    control memory usage with the watch backlog. The RTSP server now
    limits queued TCP data messages to one per stream, moving queuing of
    the data into the pipeline and leaving the RTSP connection
    responsive to RTSP messages in both directions, preventing all those
    problems.

-   Initial ULP Forward Error Correction support in rtspclientsink and
    for RECORD mode in the server.

-   API to explicitly enable retransmission requests (RTX)

-   Lots of multicast-related fixes

-   rtsp-auth: Add support for parsing .htdigest files


GStreamer VAAPI

-   this section will be filled in in due course


GStreamer OMX

-   Add support of NV16 format to video encoders input.

-   Video decoders now handle the ALLOCATION query to tell upstream
    about the number of buffers they require. Video encoders will also
    use this query to adjust their number of allocated buffers
    preventing starvation when using dynamic buffer mode.

-   The OMX_PERFORMANCE debug category has been renamed to OMX_API_TRACE
    and can now be used to track a widder variety of interactions
    between OMX and GStreamer.

-   Video encoders will now detect frame rate only changes and will
    inform OMX about it rather than doing a full format reset.

-   Various Zynq UltraScale+ specific improvements:
    -   Video encoders are now able to import dmabuf from upstream.
    -   Support for HEVC range extension profiles and more AVC profiles.
    -   We can now request video encoders to generate an IDR using the
        force key unit event.


GStreamer Editing Services and NLE

-   this section will be filled in in due course


GStreamer validate

-   this section will be filled in in due course


GStreamer Python Bindings

-   add binding for gst_pad_set_caps()

-   pygobject dependency requirement was bumped to >= 3.8

-   new audiotestsrc, audioplot, and mixer plugin examples, and a
    dynamic pipeline example


GStreamer C# Bindings

-   bindings for the GstWebRTC library


GStreamer Rust Bindings

The GStreamer Rust bindings are now officially part of the GStreamer
project and are also maintained in the GStreamer GitLab.

The releases will generally not be synchronized with the releases of
other GStreamer parts due to dependencies on other projects.

Also unlike the other GStreamer libraries, the bindings will not commit
to full API stability but instead will follow the approach that is
generally taken by Rust projects, e.g.:

1)  0.12.X will be completely API compatible with all other 0.12.Y
    versions.
2)  0.12.X+1 will contain bugfixes and compatible new feature additions.
3)  0.13.0 will _not_ be backwards compatible with 0.12.X but projects
    will be able to stay at 0.12.X without any problems as long as they
    don’t need newer features.

The current stable release is 0.12.2 and the next release series will be
0.13, probably around March 2019.

At this point the bindings cover most of GStreamer core (except for most
notably GstAllocator and GstMemory), and most parts of the app, audio,
base, check, editing-services, gl, net. pbutils, player, rtsp,
rtsp-server, sdp, video and webrtc libraries.

Also included is support for creating subclasses of the following types
and writing GStreamer plugins:

-   gst::Element
-   gst::Bin and gst::Pipeline
-   gst::URIHandler and gst::ChildProxy
-   gst::Pad, gst::GhostPad
-   gst_base::Aggregator and gst_base::AggregatorPad
-   gst_base::BaseSrc and gst_base::BaseSink
-   gst_base::BaseTransform

Changes to 0.12.X since 0.12.0

Fixed

-   PTP clock constructor actually creates a PTP instead of NTP clock

Added

-   Bindings for GStreamer Editing Services
-   Bindings for GStreamer Check testing library
-   Bindings for the encoding profile API (encodebin)

-   VideoFrame, VideoInfo, AudioInfo, StructureRef implements Send and
    Sync now
-   VideoFrame has a function to get the raw FFI pointer
-   From impls from the Error/Success enums to the combined enums like
    FlowReturn
-   Bin-to-dot file functions were added to the Bin trait
-   gst_base::Adapter implements SendUnique now
-   More complete bindings for the gst_video::VideoOverlay interface,
    especially
    gst_video::is_video_overlay_prepare_window_handle_message()

Changed

-   All references were updated from GitHub to freedesktop.org GitLab
-   Fix various links in the README.md
-   Link to the correct location for the documentation
-   Remove GitLab badge as that only works with gitlab.com currently

Changes in git master for 0.13

Fixed

-   gst::tag::Album is the album tag now instead of artist sortname

Added

-   Subclassing infrastructure was moved directly into the bindings,
    making the gst-plugin crate deprecated. This involves many API
    changes but generally cleans up code and makes it more flexible.
    Take a look at the gst-plugins-rs crate for various examples.

-   Bindings for CapsFeatures and Meta
-   Bindings for
    ParentBufferMeta,VideoMetaandVideoOverlayCompositionMeta`
-   Bindings for VideoOverlayComposition and VideoOverlayRectangle
-   Bindings for VideoTimeCode

-   UniqueFlowCombiner and UniqueAdapter wrappers that make use of the
    Rust compile-time mutability checks and expose more API in a safe
    way, and as a side-effect implement Sync and Send now

-   More complete bindings for Allocation Query
-   pbutils functions for codec descriptions
-   TagList::iter() for iterating over all tags while getting a single
    value per tag. The old ::iter_tag_list() function was renamed to
    ::iter_generic() and still provides access to each value for a tag
-   Bus::iter() and Bus::iter_timed() iterators around the corresponding
    ::pop\*() functions

-   serde serialization of Value can also handle Buffer now

-   Extensive comments to all examples with explanations
-   Transmuxing example showing how to use typefind, multiqueue and
    dynamic pads
-   basic-tutorial-12 was ported and added

Changed

-   Rust 1.31 is the minimum supported Rust version now
-   Update to latest gir code generator and glib bindings

-   Functions returning e.g. gst::FlowReturn or other “combined” enums
    were changed to return split enums like
    Result<gst::FlowSuccess, gst::FlowError> to allow usage of the
    standard Rust error handling.

-   MiniObject subclasses are now newtype wrappers around the underlying
    GstRc<FooRef> wrapper. This does not change the API in any breaking
    way for the current usages, but allows MiniObjects to also be
    implemented in other crates and makes sure rustdoc places the
    documentation in the right places.

-   BinExt extension trait was renamed to GstBinExt to prevent conflicts
    with gtk::Bin if both are imported

-   Buffer::from_slice() can’t possible return None

-   Various clippy warnings


GStreamer Rust Plugins

Like the GStreamer Rust bindings, the Rust plugins are now officially
part of the GStreamer project and are also maintained in the GStreamer
GitLab.

In the 0.3.x versions this contained infrastructure for writing
GStreamer plugins in Rust, and a set of plugins.

In git master that infrastructure was moved to the GLib and GStreamer
bindings directly, together with many other improvements that were made
possible by this, so the gst-plugins-rs repository only contains
GStreamer elements now.

Elements included are:

-   Tutorials plugin: identity, rgb2gray and sinesrc with extensive
    comments

-   rsaudioecho, a port of the audiofx element

-   rsfilesrc, rsfilesink

-   rsflvdemux, a FLV demuxer. Not feature-equivalent with flvdemux yet

-   threadshare plugin: ts-appsrc, ts-proxysrc/sink, ts-queue, ts-udpsrc
    and ts-tcpclientsrc elements that use a fixed number of threads and
    share them between instances. For more background about these
    elements see Sebastian’s talk “When adding more threads adds more
    problems - Thread-sharing between elements in GStreamer” at the
    GStreamer Conference 2017.

-   rshttpsrc, a HTTP source around the hyper/reqwest Rust libraries.
    Not feature-equivalent with souphttpsrc yet.

-   togglerecord, an element that allows to start/stop recording at any
    time and keeps all audio/video streams in sync.

-   mccparse and mccenc, parsers and encoders for the MCC closed caption
    file format.

Changes to 0.3.X since 0.3.0

-   All references were updated from GitHub to freedesktop.org GitLab
-   Fix various links in the README.md
-   Link to the correct location for the documentation

Changes in git master for 0.4

-   togglerecord: Switch to parking_lot crate for mutexes/condition
    variables for lower overhead
-   Merge threadshare plugin here
-   New closedcaption plugin with mccparse and mccenc elements
-   New identity element for the tutorials plugin

-   Register plugins statically in tests instead of relying on the
    plugin loader to find the shared library in a specific place

-   Update to the latest API changes in the GLib and GStreamer bindings
-   Update to the latest versions of all crates


Build and Dependencies

-   The MESON BUILD SYSTEM BUILD IS NOW FEATURE-COMPLETE (*) and it is
    now the recommended build system on all platforms and also used by
    Cerbero to build GStreamer on all platforms. The Autotools build is
    scheduled to be removed in the next cycle. Developers who currently
    use gst-uninstalled should move to gst-build. The build option
    naming has been cleaned up and made consistent and there are now
    feature options to enable/disable plugins and various other features
    on a case-by-case basis. (*) with the exception of plugin docs which
    will be handled differently in future

-   Symbol export in libraries is now controlled via explicit exports
    using symbol visibility or export defines where supported, to ensure
    consistency across all platforms. This also allows libraries to have
    exports that vary based on detected platform features and configure
    options as is the case with the GStreamer OpenGL integration library
    for example. A few symbols that had been exported by accident in
    earlier versions may no longer be exported. These symbols will not
    have had declarations in any public header files then though and
    would not have been usable.

-   The GStreamer FFmpeg wrapper plugin (gst-libav) now depends on
    FFmpeg 4.x and uses the new FFmpeg 4.x API and stopped relying on
    ancient API that was removed with the FFmpeg 4.x release. This means
    that it is no longer possible to build this module against an older
    system-provided FFmpeg 3.x version. Use the internal FFmpeg 4.x copy
    instead if you build using autotools, or use gst-libav 1.14.x
    instead which targets the FFmpeg 3.x API and _should_ work fine in
    combination with a newer GStreamer. It’s difficult for us to support
    both old and new FFmpeg APIs at the same time, apologies for any
    inconvenience caused.

-   Hardware-accelerated Nvidia video encoder/decoder plugins nvdec and
    nvenc can be built against CUDA Toolkit versions 9 and 10.0 now. The
    dynlink interface has been dropped since it’s deprecated in 10.0.

-   The (optional) OpenCV requirement has been bumped to >= 3.0.0 and
    the plugin can also be built against OpenCV 4.x now.

-   New sctp plugin based on usrsctp (for WebRTC data channels)

Cerbero

Cerbero is a meta build system used to build GStreamer plus dependencies
on platforms where dependencies are not readily available, such as
Windows, Android, iOS and macOS.

Cerbero has seen a number of improvements:

-   Cerbero has been ported to Python 3 and requires Python 3.5 or newer
    now

-   Source tarballs are now protected by checksums in the recipes to
    guard against download errors and malicious takeover of projects or
    websites. In addition, downloads are only allowed via secure
    transports now and plain HTTP, FTP and git:// transports are not
    allowed anymore.

-   There is now a new fetch-bootstrap command which downloads sources
    required for bootstrapping, with an optional --build-tools-only
    argument to match the bootstrap --build-tools-only command.

-   The bootstrap, build, package and bundle-source commands gained a
    new --offline switch that ensures that only sources from the cache
    are used and never downloaded via the network. This is useful in
    combination with the fetch and fetch-bootstrap commands that acquire
    sources ahead of time before any build steps are executed. This
    allows more control over the sources used and when sources are
    updated, and is particularly useful for build environments that
    don’t have network access.

-   bootstrap --assume-yes will automatically say ‘yes’ to any
    interactive prompts during the bootstrap stage, such as those from
    apt-get or yum.

-   bootstrap --system-only will only bootstrap the system without build
    tools.

-   Manifest support: The build manifest can be used in continuous
    integration (CI) systems to fixate the Git revision of certain
    projects so that all builds of a pipeline are on the same reference.
    This is used in GStreamer’s gitlab CI for example. It can also be
    used in order to re-produce a specific build. To set a manifest, you
    can set manifest = 'my_manifest.xml' in your configuration file, or
    use the --manifest command line option. The command line option will
    take precendence over anything specific in the configuration file.

-   The new build-deps command can be used to build only the
    dependencies of a recipe, without the recipe itself.

-   new --list-variants command to list available variants

-   variants can now be set on the command line via the -v option as a
    comma-separated list. This overrides any variants set in any
    configuration files.

-   new qt5, intelmsdk and nvidia variants for enabling Qt5 and hardware
    codec support. See the Enabling Optional Features with Variants
    section in the Cerbero documentation for more details how to enable
    and use these variants.

-   A new -t / --timestamp command line switch makes commands print
    timestamps


Platform-specific changes and improvements

Android

-   toolchain: update compiler to clang and NDKr18. NDK r18 removed the
    armv5 target and only has Android platforms that target at least
    armv7 so the armv5 target is not useful anymore.

-   The way that GIO modules are named has changed due to upstream GLib
    natively adding support for loading static GIO modules. This means
    that any GStreamer application using gnutls for SSL/TLS on the
    Android or iOS platforms (or any other setup using static libraries)
    will fail to link looking for the g_io_module_gnutls_load_static()
    function. The new function name is now
    g_io_gnutls_load(gpointer data). data can be NULL for a static
    library. Look at this commit for the necessary change in the
    examples.

-   various build issues on Android have been fixed.

macOS and iOS

-   various build issues on iOS have been fixed.

-   the minimum required iOS version is now 9.0. The difference in
    adoption between 8.0 and 9.0 is 0.1% and the bump to 9.0 fixes some
    build issues.

-   The way that GIO modules are named has changed due to upstream GLib
    natively adding support for loading static GIO modules. This means
    that any GStreamer application using gnutls for SSL/TLS on the
    Android or iOS platforms (or any other setup using static libraries)
    will fail to link looking for the g_io_module_gnutls_load_static()
    function. The new function name is now
    g_io_gnutls_load(gpointer data). data can be NULL for a static
    library. Look at this commit for the necessary change in the
    examples.

Windows

-   The webrtcdsp element is shipped again as part of the Windows binary
    packages, the build system issue has been resolved.

-   ‘Inconsistent DLL linkage’ warnings when building with MSVC have
    been fixed

-   Hardware-accelerated Nvidia video encoder/decoder plugins nvdec and
    nvenc build on Windows now, also with MSVC and using Meson.

-   The ksvideosrc camera capture plugin supports 16-bit grayscale video
    now

-   The wasapisrc audio capture element implements loopback recording
    from another output device or sink

-   wasapisink recover from low buffer levels in shared mode and some
    exclusive mode fixes

-   dshowsrc now implements the GstDeviceMonitor interface


Contributors

Aaron Boxer, Aleix Conchillo Flaqué, Alessandro Decina, Alexandru Băluț,
Alex Ashley, Alexey Chernov, Alicia Boya García, Amit Pandya, Andoni
Morales Alastruey, Andreas Frisch, Andre McCurdy, Andy Green, Anthony
Violo, Antoine Jacoutot, Antonio Ospite, Arun Raghavan, Aurelien Jarno,
Aurélien Zanelli, ayaka, Bananahemic, Bastian Köcher, Branko Subasic,
Brendan Shanks, Carlos Rafael Giani, Charlie Turner, Christoph Reiter,
Corentin Noël, Daeseok Youn, Damian Vicino, Dan Kegel, Daniel Drake,
Daniel Klamt, Danilo Spinella, Dardo D Kleiner, David Ing, David
Svensson Fors, Devarsh Thakkar, Dimitrios Katsaros, Edward Hervey,
Emilio Pozuelo Monfort, Enrique Ocaña González, Erlend Eriksen, Ezequiel
Garcia, Fabien Dessenne, Fabrizio Gennari, Florent Thiéry, Francisco
Velazquez, Freyr666, Garima Gaur, Gary Bisson, George Kiagiadakis, Georg
Lippitsch, Georg Ottinger, Geunsik Lim, Göran Jönsson, Guillaume
Desmottes, H1Gdev, Haihao Xiang, Haihua Hu, Harshad Khedkar, Havard
Graff, He Junyan, Hoonhee Lee, Hosang Lee, Hyunjun Ko, Ilya Smelykh,
Ingo Randolf, Iñigo Huguet, Jakub Adam, James Stevenson, Jan Alexander
Steffens, Jan Schmidt, Jerome Laheurte, Jimmy Ohn, Joakim Johansson,
Jochen Henneberg, Johan Bjäreholt, John-Mark Bell, John Bassett, John
Nikolaides, Jonathan Karlsson, Jonny Lamb, Jordan Petridis, Josep Torra,
Joshua M. Doe, Jos van Egmond, Juan Navarro, Julian Bouzas, Jun Xie,
Junyan He, Justin Kim, Kai Kang, Kim Tae Soo, Kirill Marinushkin, Kyrylo
Polezhaiev, Lars Petter Endresen, Linus Svensson, Louis-Francis
Ratté-Boulianne, Lucas Stach, Luis de Bethencourt, Luz Paz, Lyon Wang,
Maciej Wolny, Marc-André Lureau, Marc Leeman, Marco Trevisan (Treviño),
Marcos Kintschner, Marian Mihailescu, Marinus Schraal, Mark Nauwelaerts,
Marouen Ghodhbane, Martin Kelly, Matej Knopp, Mathieu Duponchelle,
Matteo Valdina, Matthew Waters, Matthias Fend, memeka, Michael Drake,
Michael Gruner, Michael Olbrich, Michael Tretter, Miguel Paris, Mike
Wey, Mikhail Fludkov, Naveen Cherukuri, Nicola Murino, Nicolas Dufresne,
Niels De Graef, Nirbheek Chauhan, Norbert Wesp, Ognyan Tonchev, Olivier
Crête, Omar Akkila, Pat DeSantis, Patricia Muscalu, Patrick Radizi,
Patrik Nilsson, Paul Kocialkowski, Per Forlin, Peter Körner, Peter
Seiderer, Petr Kulhavy, Philippe Normand, Philippe Renon, Philipp Zabel,
Pierre Labastie, Piotr Drąg, Roland Jon, Roman Sivriver, Roman Shpuntov,
Rosen Penev, Russel Winder, Sam Gigliotti, Santiago Carot-Nemesio,
Sean-Der, Sebastian Dröge, Seungha Yang, Shi Yan, Sjoerd Simons, Snir
Sheriber, Song Bing, Soon, Thean Siew, Sreerenj Balachandran, Stefan
Ringel, Stephane Cerveau, Stian Selnes, Suhas Nayak, Takeshi Sato,
Thiago Santos, Thibault Saunier, Thomas Bluemel, Tianhao Liu,
Tim-Philipp Müller, Tobias Ronge, Tomasz Andrzejak, Tomislav Tustonić,
U. Artie Eoff, Ulf Olsson, Varunkumar Allagadapa, Víctor Guzmán, Víctor
Manuel Jáquez Leal, Vincenzo Bono, Vineeth T M, Vivia Nikolaidou, Wang
Fei, wangzq, Whoopie, Wim Taymans, Wind Yuan, Wonchul Lee, Xabier
Rodriguez Calvar, Xavier Claessens, Haihao Xiang, Yacine Bandou,
Yeongjin Jeong, Yuji Kuwabara, Zeeshan Ali,

… and many others who have contributed bug reports, translations, sent
suggestions or helped testing.


Bugs fixed in 1.16

-   this section will be filled in in due course

More than XXX bugs have been fixed during the development of 1.16.

This list does not include issues that have been cherry-picked into the
stable 1.16 branch and fixed there as well, all fixes that ended up in
the 1.16 branch are also included in 1.16.

This list also does not include issues that have been fixed without a
bug report in bugzilla, so the actual number of fixes is much higher.


Stable 1.16 branch

After the 1.16.0 release there will be several 1.16.x bug-fix releases
which will contain bug fixes which have been deemed suitable for a
stable branch, but no new features or intrusive changes will be added to
a bug-fix release usually. The 1.16.x bug-fix releases will be made from
the git 1.16 branch, which is a stable branch.

1.16.0

1.16.0 is scheduled to be released in April 2019.


Known Issues

-   possibly breaking/incompatible changes to properties of wrapped
    FFmpeg decoders and encoders (see above).

-   The way that GIO modules are named has changed due to upstream GLib
    natively adding support for loading static GIO modules. This means
    that any GStreamer application using gnutls for SSL/TLS on the
    Android or iOS platforms (or any other setup using static libraries)
    will fail to link looking for the g_io_module_gnutls_load_static()
    function. The new function name is now
    g_io_gnutls_load(gpointer data). See Android/iOS sections above for
    further details.


Schedule for 1.18

Our next major feature release will be 1.18, and 1.17 will be the
unstable development version leading up to the stable 1.18 release. The
development of 1.17/1.18 will happen in the git master branch.

The plan for the 1.18 development cycle is yet to be confirmed, but it
is expected that feature freeze will be around July 2019 followed by
several 1.17 pre-releases and the new 1.18 stable release in
August/September.

1.18 will be backwards-compatible to the stable 1.16, 1.14, 1.12, 1.10,
1.8, 1.6, 1.4, 1.2 and 1.0 release series.

------------------------------------------------------------------------

_These release notes have been prepared by Tim-Philipp Müller with_
_contributions from Sebastian Dröge, Guillaume Desmottes and Matthew
Waters._

_License: CC BY-SA 4.0_
