[FFmpeg-devel] [PATCH 2/3] ffmpeg.c: refine picking default video stream

[Andreas Rheinhardt]

Anton Khirnov:
> Quoting Michael Niedermayer (2020-10-21 13:17:46)
>>
>> are we talking about the same thing ?
>> ./ffmpeg  -i ~/tickets/4496/08_lect_01.rm  file.avi
>>
>> produces a output over 1 hour long before the patch, theres no seek to before EOF
>>
>> ./ffmpeg  -i ~/tickets/4496/08_lect_01.rm  file-new.avi
>>
>> after the patch the output is empty
>>
>> IMHO, its important to remove access to internal fields from applications.
>> its important to cleanup code but its also important to do the cleanup
>> cleanly. And just droping everything thats in the way instead of spending
>> the hour(s) to do it properly. That is IMHO tainted cleanup, as if you
>> wash a dirty surface with dirty water ;)
> 
> Do you have any actual suggestions as to what a "clean" solution should
> look like? "Not break any samples" is not a vary practical one, since I
> don't have all your samples and besides is too restrictive, since any
> change can potentially break some workflow [1].
> 
> How about exporting a per-AVStream flag that indicates whether there
> were every any packets seen for that stream? That would allow to keep
> current functionality in ffmpeg.c and still avoid exporting too much
> detail about the inner workings of avformat_find_stream_info().
> 
Where would you add this flag to AVStream? Given that ffmpeg uses
internal fields there is no good solution to this.

- Andreas