Bug 262972

Summary:	keyFramesDecoded > 0 while framesDecoded == 0
Product:	WebKit	Reporter:	ronakk
Component:	WebRTC	Assignee:	youenn fablet <youennf>
Status:	RESOLVED FIXED
Severity:	Normal	CC:	philipp.hancke, webkit-bug-importer, youennf
Priority:	P2	Keywords:	InRadar
Version:	Safari 17
Hardware:	Unspecified
OS:	Unspecified

Description ronakk 2023-10-10 12:27:31 PDT

Hi Folks,

Our WebRTC based application has seen an increase in failed sessions after the iOS 17 update. After some debugging we noticed that on iPhone for all failure sessions the number of keyFramesDecoded is > 0 while the number of framesDecoded == 0. According to the WebRTC standard this should not be possible: "This is a subset of framesDecoded. framesDecoded - keyFramesDecoded gives you the number of delta frames decoded.", so this seems to be a bug in the Safari WebRTC implementation on iOS17.

Comment 1 :fippo 2023-10-10 23:18:59 PDT

that particular statistic in libWebRTC has been wrong, the fix is coming to webrtc M118 as noted in https://groups.google.com/g/discuss-webrtc/c/6FL4yW3UdZg

Comment 2 youenn fablet 2023-10-11 07:46:59 PDT

As per fippo's link, the device receives key frames but apparently the decoding fails.
@ronakk, any more information you can share with us? It might be difficult to investigate without additional info.

Comment 3 Radar WebKit Bug Importer 2023-10-11 07:54:39 PDT

<rdar://problem/116810102>

Comment 4 youenn fablet 2023-10-12 03:53:56 PDT

Pull request: https://github.com/WebKit/WebKit/pull/18991

Comment 5 EWS 2023-10-12 09:24:53 PDT

Committed 269258@main (248020847da1): <https://commits.webkit.org/269258@main>

Reviewed commits have been landed. Closing PR #18991 and removing active labels.