1194708 - SPS not properly detected in some videos

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, defect)

Description

[Jean-Yves Avenard [:jya]]

A H264 NAL is made of:
From Rec. ITU-T H.264
7.4.1 NAL unit semantics

* forbidden_zero_bit shall be equal to 0 (1 bit)
* nal_ref_idc not equal to 0 specifies that the content of the NAL unit contains a sequence parameter set, a sequence parameter set extension, a subset sequence parameter set, a picture parameter set, a slice of a reference picture, a slice data partition of a reference picture, or a prefix NAL unit preceding a slice of a reference picture. (2 bits)
* nal_unit_type (5 bits)

We always assumed that nal_ref_idc was set to 11.

This can cause the SPS to not be found in some videos (BBC)

Comment 1

[Jean-Yves Avenard [:jya]]

Attachment: Properly find SPS NAL in some H264 streams.

With some encoding, we didn't detect the SPS. With AVC3 stream it would cause playback to never start on mac or linux (ffmpeg)

Comment 2

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/13b813170d8e

Comment 3

[Jean-Yves Avenard [:jya]]

Comment on attachment 8648054 [details] [diff] [review]
Properly find SPS NAL in some H264 streams.

Approval Request Comment
[Feature/regressing bug #]: 1128381
[User impact if declined]: Media won't play. BBC videos won't start.
[Describe test coverage new/current, TreeHerder]: Locally tested, inbound
[Risks and why]: Extremely low; this is just implementing the spec more accurately.
[String/UUID change made/needed]: None

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/13b813170d8e

Comment 5

[Sylvestre Ledru [:Sylvestre]]

Comment on attachment 8648054 [details] [diff] [review]
Properly find SPS NAL in some H264 streams.

Improve the media situation, taking it.

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/6b8ab5760fa7

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/6fbcbf05900f