[FFmpeg-devel] [PATCH] avpacket: RFC for ABI bump additions

[Lynne]

Jan 23, 2021, 21:04 by cus at passwd.hu:

>
>
> On Sat, 23 Jan 2021, Lynne wrote:
>
>> This is an RFC about the upcoming additions to the AVPacket structure
>> (whose size is still part of the ABI, so we need to plan for any changes).
>>
>> The current RFC patch adds 3 fields:
>>     - "void *opaque;" for the user to use as they wish, same as AVFrame.opaque
>>     - "void *opaque_ref;" for more permanent and propagating user data, same as AVFrame.opaque_ref
>>
>
> These seem legit.
>
>>     - "AVRational time_base;" which will be set to indicate the time base of the packet's timestamps
>>
>
> Why? It seems redundant and it will not be clear when to use to use stream/bsf/etc time base and when embedded AVPacket timebase. So I don't think this is a good idea.
>

I'd like to switch to using this to avoid the dance you have to do with
avformat init, where you have to give it your packet's time_base in the stream time_base
then init, which then sets the time_base in the same field you provided your time_base,
and then you have to rescale the timestamps of packets to that timebase.
Wouldn't it be simpler to just give avformat packets and let it adjust the
packet time base internally as it sees fit and store it in a private_ref field?

It was a struggle figuring out how to init avformat properly since none of this
was documented when I was implementing it, and it was only thanks to
comments in mpv's source that I figured it out.