[FFmpeg-devel] [PATCH 10/18] lavf: move AVStream.*index_entries* to AVStreamInternal

[James Almer]

On 11/16/2020 12:25 PM, Hendrik Leppkes wrote:
> On Mon, Nov 16, 2020 at 4:20 PM James Almer <jamrial at gmail.com> wrote:
>>
>> On 11/16/2020 3:01 AM, Anton Khirnov wrote:
>>> Quoting Xiang, Haihao (2020-11-16 06:16:55)
>>>>
>>>> This change breaks the compiling of gst-libav (
>>>> https://gitlab.freedesktop.org/gstreamer/gst-libav), I filed
>>>> https://trac.ffmpeg.org/ticket/8988 to track this regression.
>>>
>>> This is not a regression, it's a bug in gst-libav. These fields are
>>> private and have always been private, applications accessing them are
>>> broken.
>>
>> Looking at that ticket, it seems gst-libav wants the timestamp for a
>> given index entry. Unless this can already be achieved in some other
>> way, it could maybe be implemented cleanly with a new public function
>> (We have av_index_search_timestamp() to fetch an index from a timestamp
>> after all).
> 
> I also like being able to access the index, it can be used by players
> to efficiently offer seeking straight to keyframes (eg. index
> entries), which basically requires iterating over the full index and
> getting the full information (timestamp, flags at least)
> 
> - Hendrik

What do you suggest, implement something like what you added to you 
LAVFilters fork? I don't know if returning a pointer to a given 
AVIndexEntry is ideal. If that were the case, then it wouldn't be an 
internal field.

Perhaps something like

int av_index_get_entries_count(AVStream *st);
int av_index_get_timestamp(AVStream *st, int64_t *timestamp, int *flags, 
int idx);

Where timestamp and flags are output parameters in the latter, 
containing the relevant AVIndexEntry values.