[Libav-user] Hardware accell encoding

Leandro Raffo ljraffo at gmail.com
Sat Sep 10 18:01:15 EEST 2016

2016-09-09 18:56 GMT-03:00 Charles <linux2 at orion15.org>:
> On 09/09/2016 04:17 PM, Leandro Raffo wrote:
>> 2016-09-09 15:59 GMT-03:00 Charles <linux2 at orion15.org>:
>>>> I'm trying to encode AVFrames using the GPU from C code, so I was
>>>> trying to see how ffmpeg's source code was doing it and asking for a
>>>> pointer on it (or its location lol). I've already encoded directly
>>>> with ffmpeg (to see its working) but I need to encode random AVFrames
>>>> not an entire video. Also giving a yuv420 video to the Nvidia ENC
>>>> samples produces a corrupted video.
>>> nvenc is going to encode yuv video into h264 stream, I am not sure the
>>> output format is what you want.
>>> To get "random" frames encoded, you will have to do something like GOP=1
>>> and
>>> mark all frames key frames somehow.
>>> Sounds like you are trying to create a slide show from random frames in a
>>> video stream?
>>> Pure theory YMMV...
>>> If you want to use nvenc directly you need to transform AVFrame to
>>> EncodeFrameConfig
>>> See
>>> NVENCSTATUS CNvEncoder::EncodeFrame(EncodeFrameConfig *pEncodeFrame, bool
>>> bFlush, uint32_t width, uint32_t height)
>>> Should be able to create your own convertAvFrametoEncoded
>>> REF: convertYUVpitchtoNV12 convertYUVpitchtoYUV444
>>> Setting ecoded->yuv[0], encoded->yuv[1], encoded->yuv[2], dstwidth,
>>> dstheight from
>>> av_frame->data[0] av_frame->data[1] av_frame->data[2], av_frame->width,
>>> av_frame->height, av_frame->linesize
>>> but I think the output will not be a "VIDEO FRAME"
>>> Thanks
>>> cco
>> I have RGB images of a video that I was converting to AVFrames and I
>> wanted to encode in real time without incurring in heavy CPU usage.
>> Basically offload the hard part to the GPU. I thought ffmpeg api would
>> expose some kind of  functionality for this (I've seen code doing
>> decoding with VDPAU). I'll keep checking the nvidia examples( I was
>> avoiding them mainly because of the amount of boilerplate that I don't
>> have a clue what is doing and because it encoded garbage.) and see If
>> I can do it with your pointers. Thanks!
> If you use ffmpeg and specify the h264_nvenc it will use almost no cpu
> Here is a mostly working example, it runs as a pthread just push frames
> (RGB)
> https://gist.github.com/LinuxwitChdoCtOr/1fbfc44443de8f0fcf6a742f5562376d
> You will need to specify which h264 enoder to use if you have more than one
> Just FYI it is still a lot of code
> Thanks
> cco

Holy moly, didn't expect you to write a working example at all, thanks
I'll check it out.

More information about the Libav-user mailing list