[FFmpeg-devel] [PATCH] libavformat/matroskadec.c: Eliminate spurious "File is broken, keyframes not correctly marked!" in valid WebM

Monty Montgomery xiphmont at gmail.com
Wed Sep 11 09:37:18 CEST 2013


> I think it was supposed to warn for both cases.

Ah, OK.

> To my knowledge there were also files where nothing at all was marked as keyframe, causing seeking to not work at all.

I don't think that's an issue here.

> Is it really ok/sensible to not have a keyframe marked as such?

That doesn't appear to be the problem; the warning is tripped by audio
blocks, not video.  That is,  skip_to_keyframe is set, and we land on
an audio block... which, strictly speaking, is indeed supposed to
flagged as a keyframe.

I suppose it would also work to alter:

    if (matroska->skip_to_keyframe && track->type !=
MATROSKA_TRACK_TYPE_SUBTITLE){

to

    if (matroska->skip_to_keyframe && track->type !=
MATROSKA_TRACK_TYPE_SUBTITLE && track->type !=
MATROSKA_TRACK_TYPE_AUDIO){

Monty

On Wed, Sep 11, 2013 at 2:49 AM, Reimar Döffinger
<Reimar.Doeffinger at gmx.de> wrote:
>
>
> On 11.09.2013, at 08:12, Monty Montgomery <xiphmont at gmail.com> wrote:
>
>> Oops, let me resend with a properly tagged subject line so that devs
>> can find this later...
>>
>> As of last year, ffmpeg and apps making use of ffmpeg (such as
>> mplayer) complain about a great many valid webm files ("File is
>> broken, keyframes not correctly marked!")   The obvious cause is the
>> patch to Trac bug #1003.
>>
>> I believe I understand what the fix was attempting, and have an
>> alternate fix that avoids the spurious errors.  It properly handles
>> (and squawks) about the example file attached to Trac #1003.  There is
>> no functional change to the code or data path, only whether or not the
>> error is emitted.
>
> I think it was supposed to warn for both cases.
> To my knowledge there were also files where nothing at all was marked as keyframe, causing seeking to not work at all.
> Is it really ok/sensible to not have a keyframe marked as such?
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