[FFmpeg-devel] [PATCH] avformat: add H264 and HEVC support in IVF muxer

[James Almer]

On 10/14/2018 9:59 AM, Michael Niedermayer wrote:
> On Sun, Oct 14, 2018 at 01:29:53PM +0300, Jan Ekström wrote:
>> On Sun, Oct 14, 2018 at 1:27 PM Jan Ekström <jeebjp at gmail.com> wrote:
>>>
>>> On Sun, Oct 14, 2018 at 3:17 AM Michael Niedermayer
>>> <michael at niedermayer.cc> wrote:
>>>>
>>>> On Fri, Oct 12, 2018 at 01:13:45AM +0100, Derek Buitenhuis wrote:
>>>>> On 11/10/2018 23:39, Alex Sukhanov wrote:
>>>>>> The only "spec" I'm aware of:https://wiki.multimedia.cx/index.php/IVF
>>>>>
>>>>> Yeah, not really a spec.
>>>>>
>>>>> I have no strong objections, I guess.
>>>>
>>>> so IIUC noone is against this ?
>>>> if so i will apply the last patch in a few days unless i forget or
>>>> someone else does before
>>>>
>>>> thx
>>>>
>>>
>>> As mentioned, since this is nothing should have ever been used outside
>>> of one of GOOG's legacy systems, I would only apply this with a
>>> warning and strictness requirement of experimental or whatever level
>>> matches these sorts of cases.
>>>
>>
>> For the record, this was regarding the muxer so that unknowing people
>> will not generate such files that nothing else can read.
> 
> If you choose a random container and store a random codec in it (which you can do)
> chances are theres not much that will play it.
> 
> for example i just tried muxing a stream of png images into mpeg and FFmpeg
> does that without complaining.
> ./ffmpeg -i matrixbench_mpeg2.mpg -vcodec png test.mpeg
> 
> So if we do not check this for a major format that has a proper specification
> which i belive nowhere allows png
> 
> Why should we add a limitation on a format that has nothing saying that you
> cannot put some other codec into it ?

The proper thing to do would be to effectively disallow such invalid
muxing scenarios, fixing this instead of adding even more wrong cases to
the pile.
I'm fairly sure we blocked a patch to allow muxing hevc into flv years
ago. That's what needs to be done in general.