[FFmpeg-devel] [PATCH] adtsenc: Add ability to specify MPEG ID

[Marvin Scholz]

On 16 Jul 2020, at 17:27, Kieran Kunhya wrote:

> On Thu, 16 Jul 2020 at 16:25, Marvin Scholz <epirat07 at gmail.com> 
> wrote:
>
>> ---
>>
>> This stills lacks docs, as I first want an overall opinion on this
>> approach or possible other solutions I should choose for this.
>>
>
> What uses this?

It's needed when concatenating streams with existing ADTS streams that 
have the same parameters,
except for the differing MPEG ID.
Such a stream would be invalid if the MPEG IDs are different as then the 
fixed header part of
the ADTS header changes mid-stream, which is not allowed.

FFmpeg does not care and still works fine for such broken streams but 
some other players do
and will break trying to play such streams.
I could not find any reason for the choice of used MPEG ID in FFmpeg, 
and in the specifications
it was not clear to me either if there is even one "right" one to be 
used, so the best
way to solve this seemed to allow to choose it.

>
> Kieran