[FFmpeg-devel] [PATCH] lavc/cuvid: fail early if GPU can't handle video parameters

[Pavel Koshevoy]

On 01/22/2017 04:58 AM, wm4 wrote:
> On Sat, 21 Jan 2017 10:35:50 -0700
> Pavel Koshevoy <pkoshevoy at gmail.com> wrote:
>
>> On Sat, Jan 21, 2017 at 10:27 AM,  <pkoshevoy at gmail.com> wrote:
>>> From: Pavel Koshevoy <pkoshevoy at gmail.com>

<snip>

>>> -    ret = cuvid_test_dummy_decoder(avctx, &ctx->cuparseinfo);
>>> +    ret = cuvid_test_dummy_decoder(avctx, &ctx->cuparseinfo,
>>> +                                   probed_chroma_format,
>>> +                                   probed_width,
>>> +                                   probed_height);
>>>       if (ret < 0)
>>>           goto error;
>>>
>>> --
>>> 2.9.2
>>>   
>>
>> Despite wm4 objections I am resubmitting this patch, because I can
>> find no other reasonable method for rejecting ffmpeg cuvid decoder
>> when it can't handle a given video stream.  An unreasonable
>> alternative would be to duplicate the work that cuvid.c does
>> internally on my application side, and that would be of little benefit
>> to me and to ffmpeg -- I might as well use the nvenc APIs directly
>> then.  I still see this patch as an improvement.
> PS:
>
> Actually, cuvid is a bit different from normal hwaccel and I confused
> that (blame Sunday "morning").
>
> In this case, do you just want the cuvid to gracefully exit the ffmpeg.c
> process if decoding is not supported? In that case, this would be much
> simpler:
>
> 1. Return a special error code from cuvid that signals unsupported
>     format
> 2. Make ffmpeg.c check for this error code, and stop transcoding with
>     an error if it's encountered


I am not working with ffmpeg.c -- I am calling ffmpeg public APIs from my 
application.  The 1. point above is essentially what my patch does.  The real 
problem is that CUVID only reports an error at cuvidCreateDecoder time, and not 
later when I attempt to decode 8K or 5K video -- it just swallows packets and 
never outputs anything (no errors, no callbacks, nothing).

Pavel.