[FFmpeg-devel] [PATCH][RFC] avcodec/avutil: Add timeline side data

[Jan Ekström]

On Wed, Mar 28, 2018 at 9:12 PM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
>> +    /**
>> +     * An in-order array of entries for the given timeline.
>> +     * Each entry contains information on which samples to display for a
>> +     * particular edit.
>> +     */
>> +    AVTimelineEntry *entries;
>
> This is problematic as its non extensible. (unless iam missing something)
> Consider that a field is added to AVTimelineEntry, the entries array would
> have a larger element size and that would require all user apps to be rebuild
>

So you would prefer some sort of iterator? Or a size entry like with
some of the entries in AVEncryptionInfo? I have a feeling this was
based off of the following added into AVEncryptionInfo:
+    AVSubsampleEncryptionInfo *subsamples;
+    uint32_t subsample_count;

Which now would seem to be similarly not being extendable?

> Also, if you want to support quicktime more fully theres more needed.
> QT can for example switch even between codecs mid stream IIRC
> not sure we want to support this
>

Thankfully, that has little to do with virtual timelines (edit lists)
as far as I can tell?

Jan