Bug 201870 – [GStreamer] isAVC1CodecSupported is crashing several media source tests due to avc1.4d4001 codec type

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Charlie Turner]

GStreamerRegistryScanner::isAVC1CodecSupported is a little sloppy not checking NULL returns from the gst_codec_utils* family which is causing the crashes. But there's a deeper problem, the NULL return is for when the h264 codec utility thinks there's an erroneous input. Particularly, it doesn't like the level_idc in the SPS for avc1.4D4001. There's nothing wrong with that according to the spec, so there's two bugs,

  1. Fix the sloppy NULL checking in WebKit
  2. Fix GStreamer to correctly parse the level_idc

[Charlie Turner]

Created attachment 378962 [details]
Patch

[Charlie Turner]

I am mistaken about point 2. In fact, the web tests are doing some weird encoding level idc's with multiplying by 10. The GStreamer function is expecting the correct things, so we have to special case here for test conformance.

[Xabier Rodríguez Calvar]

Comment on attachment 378962 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=378962&action=review

> Source/WebCore/platform/graphics/gstreamer/GStreamerRegistryScanner.cpp:322
> +    char levelAsStringFallback[2] = { '\0', '\0' };

This is a bit too tricky so I would recommend adding a with this bug number to enable a very quick access to the info.

[Philippe Normand]

Instead of a bug link I would suggest an explanation similar to the one present in the ChangeLog (or copy/paste :)) because when ChangeLogs roll-over, keeping track of the code change reasoning becomes harder.

[Charlie Turner]

Created attachment 379359 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 379359 [details]
Patch for landing

Rejecting attachment 379359 [details] from commit-queue.

Failed to run "['/Volumes/Data/EWS/WebKit/Tools/Scripts/webkit-patch', '--status-host=webkit-queues.webkit.org', '--bot-id=webkit-cq-01', 'validate-changelog', '--check-oops', '--non-interactive', 379359, '--port=mac']" exit_code: 1 cwd: /Volumes/Data/EWS/WebKit

ChangeLog entry in Source/WebCore/ChangeLog contains OOPS!.

Full output: https://webkit-queues.webkit.org/results/13059974

[Charlie Turner]

Created attachment 379361 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 379361 [details]
Patch for landing

Clearing flags on attachment: 379361

Committed r250227: <https://trac.webkit.org/changeset/250227>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.