1242465 - [Static Analysis][Logically dead code] In function SupportsMimeType from FFmpegDecoderModule.h

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, defect, P5)

Description

[Andi [:andi]]

The Static Analysis tool Coverity added that due to it's value, audioCodec = AV_CODEC_ID_NONE execution cannot reach the expression audioCodec inside this statement: 

>>   AVCodecID codec = audioCodec != AV_CODEC_ID_NONE ? audioCodec : videoCodec;

We can refactor this portion of the code in order to best suit our implementation based of #ifdef USING_MOZFFVPX

Comment 1

[Andi [:andi]]

Attachment: MozReview Request: Bug 1242465 - when defined USING_MOZFFVPX use by default videoCodec in FindAVCodec. r?jya

Review commit: https://reviewboard.mozilla.org/r/32289/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/32289/

Comment 2

[Chris Pearce [:cpearce (Not reading bugmail)]]

Comment on attachment 8711657 [details]
MozReview Request: Bug 1242465 - when defined USING_MOZFFVPX use by default videoCodec in FindAVCodec. r?jya

jya is a better reviewer for things ffmpeg related.

Comment 3

[Jean-Yves Avenard [:jya]]

This seems like a false positive to me. It is not dead code (or at least my definition of dead code). audioCodec is always NONE so we only test for video codec only.

Comment 4

[Jean-Yves Avenard [:jya]]

Comment on attachment 8711657 [details]
MozReview Request: Bug 1242465 - when defined USING_MOZFFVPX use by default videoCodec in FindAVCodec. r?jya

https://reviewboard.mozilla.org/r/32289/#review29105

::: dom/media/platforms/ffmpeg/FFmpegDecoderModule.h:71
(Diff revision 1)
> +

if we want to be that anal, then reorganise the structure so we only have a single conditional block based on MOZ_FFVPX by moving the search for the video codec above the block

Comment 5

[Andi [:andi]]

Comment on attachment 8711657 [details]
MozReview Request: Bug 1242465 - when defined USING_MOZFFVPX use by default videoCodec in FindAVCodec. r?jya

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/32289/diff/1-2/

Comment 6

[Jean-Yves Avenard [:jya]]

Comment on attachment 8711657 [details]
MozReview Request: Bug 1242465 - when defined USING_MOZFFVPX use by default videoCodec in FindAVCodec. r?jya

https://reviewboard.mozilla.org/r/32289/#review29257

Should add that this really was a false positive. Both gcc and clang optimise this code to remove all handling of audioCodec.

Comment 7

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/5d5ead7b7049

Comment 8

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/5d5ead7b7049

Comment 9

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/5d5ead7b7049