[FFmpeg-devel] [PATCH] avformat/fivdec: cached keyframes before video or audio stream was created

[XinZheng Zhang]

On Wed, Jul 27, 2016 at 10:17 AM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> On Wed, Jul 27, 2016 at 09:56:02AM +0800, XinZheng Zhang wrote:
>> On Wed, Jul 27, 2016 at 7:25 AM, Michael Niedermayer
>> <michael at niedermayer.cc> wrote:
>> > On Wed, Jul 27, 2016 at 01:31:29AM +0800, XinZheng Zhang wrote:
>> >> On Wed, Jul 27, 2016 at 1:12 AM, Michael Niedermayer
>> >> <michael at niedermayer.cc> wrote:
>> >> > On Tue, Jul 26, 2016 at 08:17:46PM +0800, Xinzheng Zhang wrote:
>> > [...]
>> >> >> +
>> >> >> +    AVStream *streams[2] = {vstream, astream};
>> >> >> +    for (i = 0; i < 2; i++) {
>> >> >> +        current_stream = streams[i];
>> >> >> +        if (current_stream && current_stream->nb_index_entries==0) {
>> >> >> +            for (j = 0; j < flv->keyframe_count; j++) {
>> >> >> +                av_add_index_entry(current_stream, flv->keyframe_filepositions[j], flv->keyframe_times[j] * 1000,
>> >> >> +                                   0, 0, AVINDEX_KEYFRAME);
>> >> >> +            }
>> >> >> +        }
>> >> >> +    }
>> >> >> +
>> >> >> +    // free keyframe index only if all expected streams have been created
>> >> >> +    if (((vstream && vstream->nb_index_entries>0) || !flv->vhead_exists) &&
>> >> >> +        ((astream && astream->nb_index_entries>0) || !flv->ahead_exists)) {
>> >> >> +        av_freep(&flv->keyframe_times);
>> >> >> +        av_freep(&flv->keyframe_filepositions);
>> >> >> +        flv->keyframe_count = 0;
>> >> >> +    }
>> >> >> +}
>> >> >
>> >> > spliting add_keyframes_index() out must be in a seperate patch
>> >> >
>> >> > also i would not trust the *head_exists flags, IIRC they can be
>> >> > wrong and they are not needed
>> >> > the function should just take the table load it with
>> >> > av_add_index_entry() and free the table.
>> >> > The rest should not be needed
>> >> > should be much simpler unless iam missing something
>> >> >
>> >> >
>> >>
>> >> If I don't trust the head_exists flags, when should I free the index table?
>> >> Should I keep the index util both a\v stream have been loaded or keep
>> >> it util the flv_read_close().
>> >
>> > the table was freed after av_add_index_entry()
>> > that should still work fine unless i miss somethig
>> >
>>
>> [meta]-[v]-[v]..........................[a]
>> In this case both video and audio stream share the same index table.
>> I am not know whether the audio stream exists until the first audio
>> packet parsed.
>> I thought that I should keep the index until all the streams have been loaded.
>
> in the example above the video key frame table would be loaded
> and added into the video stream once it has been created, and
> freed afterwards
> nothing is done with audio (currently or after the change)
>
> if the audio table is prior the video one its loaded and freed once
> the video table is encountered
>
> do i miss something ?
>

Now I understand it.
Before that I thought that both streams have to install the index table.

> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> There will always be a question for which you do not know the correct answer.
>
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