[FFmpeg-devel] [PATCH] (for discussion): nvenc: fix wrong aspect ratio for 720x576 and 720x480 resolution

Timo Rothenpieler timo at rothenpieler.org
Mon Feb 13 00:15:05 EET 2017

On 2/12/2017 10:43 PM, Miroslav Slugeň wrote:
> Dne 12.2.2017 v 22:31 Timo Rothenpieler napsal(a):
>> On 2/12/2017 10:25 PM, Miroslav Slugeň wrote:
>>> This patch is for discussion only, not ready to commit yet and maybe
>>> newer will be.
>>> NVENC in current CUDA 8 SDK is setting wrong aspect ratio when encoding
>>> resolution 720x576 and 720x480 and using AR 4:3 or 16:9 it will encode
>>> to h264 header that 15:11 and 20:11 is used. This is very very very ugly
>>> way how to fix it. I hope someone in NVIDIA will fix this soon, because
>>> all encoded streams are not displayed correctly for example in videojs
>>> player.
>> nvenc.c had some compensation for this, which was somewhat recently
>> removed, because nvidia fixed something regarding it:
>> http://git.videolan.org/?p=ffmpeg.git;a=commit;h=829db8effd76b579ae9aca5ee8f85d3ade6af253
> I know that, i am monitoring all nvenc and cuvid changes in ffmpeg.
> Fix is not working anymore in current drivers. What is working is if you
> set aspect ratio 16000x9001 it will give you almost correct output, but
> fixing this in h264 SPP is better solution.
> M.

Imo the best would be to contact nvidia about this potential bug.
Maybe a leftover from removing the old compensation logic?
Actually fixing the driver would definitely be the best solution here.

Adding some of the @nvidia.com people from this ML to CC, maybe they can
forward the issue to the right place.

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