Attachment 350192 Details for Bug 189782 – Patch

[patch] Patch

bug-189782-20180920152934.patch (text/plain), 3.25 KB, created by Alicia Boya García on 2018-09-20 06:29:35 PDT

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Creator: Alicia Boya García

Created: 2018-09-20 06:29:35 PDT

Size: 3.25 KB

patch

obsolete

>Subversion Revision: 236166
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index 9fcb657142ed7fe2503cc27f7bdae634efdf21e4..d3d1bc30302022bea5a311dac1fa0d5522dfc30b 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,24 @@
>+2018-09-20  Alicia Boya GarcÃa  <aboya@igalia.com>
>+
>+        [MSE] Use some tolerance when deciding whether a frame should be appended to the decode queue
>+        https://bugs.webkit.org/show_bug.cgi?id=189782
>+
>+        Reviewed by Xabier Rodriguez-Calvar.
>+
>+        Ideally, container formats should use exact timestamps and frames
>+        should not overlap. Unfortunately, there are lots of files out there
>+        where this is not always the case.
>+
>+        This is particularly a problem in WebM, where timestamps are expressed
>+        in a power of 10 timescale, which forces some rounding.
>+
>+        This patch makes SourceBuffer allow frames with a small overlaps
>+        (<=1ms) as those usually found in WebM. 1 ms is chosen because it's
>+        the default time scale of WebM files.
>+
>+        * Modules/mediasource/SourceBuffer.cpp:
>+        (WebCore::SourceBuffer::sourceBufferPrivateDidReceiveSample):
>+
> 2018-09-19  Philippe Normand <pnormand@igalia.com>
> 
>         [GStreamer] Add support for AV1 decoding
>diff --git a/Source/WebCore/Modules/mediasource/SourceBuffer.cpp b/Source/WebCore/Modules/mediasource/SourceBuffer.cpp
>index 20aa84b3d0bf4626b828b1bbf45af2fbc62afb4c..afd120075a410ac509340f4b5ea0818f759618ee 100644
>--- a/Source/WebCore/Modules/mediasource/SourceBuffer.cpp
>+++ b/Source/WebCore/Modules/mediasource/SourceBuffer.cpp
>@@ -1688,7 +1688,17 @@ void SourceBuffer::sourceBufferPrivateDidReceiveSample(MediaSample& sample)
>         // Add the coded frame with the presentation timestamp, decode timestamp, and frame duration to the track buffer.
>         trackBuffer.samples.addSample(sample);
> 
>-        if (trackBuffer.lastEnqueuedDecodeEndTime.isInvalid() || decodeTimestamp >= trackBuffer.lastEnqueuedDecodeEndTime) {
>+        // Note: The terminology here is confusing: "enqueuing" means providing a frame to the inner media framework.
>+        // First, frames are inserted in the decode queue; later, at the end of the append all the frames in the decode
>+        // queue are "enqueued" (sent to the inner media framework) in `provideMediaData()`.
>+        //
>+        // In order to check whether a frame should be added to the decode queue we check whether it starts after the
>+        // lastEnqueuedDecodeEndTime or even a bit before that to accomodate files with imprecise timing information.
>+        //
>+        // There are many files out there where the frame times are not perfectly contiguous, therefore a tolerance is needed.
>+        // For instance, most WebM files are muxed rounded to the millisecond (the default TimecodeScale of the format).
>+        const MediaTime contiguousFrameTolerance = MediaTime(1, 1000);
>+        if (trackBuffer.lastEnqueuedDecodeEndTime.isInvalid() || decodeTimestamp >= (trackBuffer.lastEnqueuedDecodeEndTime - contiguousFrameTolerance)) {
>             DecodeOrderSampleMap::KeyType decodeKey(sample.decodeTime(), sample.presentationTime());
>             trackBuffer.decodeQueue.insert(DecodeOrderSampleMap::MapType::value_type(decodeKey, &sample));
>         }

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