[Libav-user] Can't decode more than 5 video streams using libav+hwaccel.

[Ахмед Анам]

>  Are the video streams 4K? My guest is you are running out of memory on the GPU.

No, the streams have HD resolution. I run my programm with debug log level and here is output:

[h264 @ 0000013f85b22440] Failed setup for format cuda: hwaccel initialisation returned error
[h264 @ 0000013f85b22440] Format cuda not usable, retrying get_format() without it.
[h264 @ 0000013f85b22440] decode_slice_header error
[h264 @ 0000013f85b22440] no frame!
[h264 @ 0000013f85b22440] nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
[h264 @ 0000013f85b22440] Format cuda chosen by get_format().
[h264 @ 0000013f85b22440] Format cuda requires hwaccel initialisation.
[h264 @ 0000013f85b22440] Loaded lib: nvcuvid.dll
[h264 @ 0000013f85b22440] Loaded sym: cuvidGetDecoderCaps
[h264 @ 0000013f85b22440] Loaded sym: cuvidCreateDecoder
[h264 @ 0000013f85b22440] Loaded sym: cuvidDestroyDecoder
[h264 @ 0000013f85b22440] Loaded sym: cuvidDecodePicture
[h264 @ 0000013f85b22440] Loaded sym: cuvidGetDecodeStatus
[h264 @ 0000013f85b22440] Loaded sym: cuvidReconfigureDecoder
[h264 @ 0000013f85b22440] Loaded sym: cuvidMapVideoFrame64
[h264 @ 0000013f85b22440] Loaded sym: cuvidUnmapVideoFrame64
[h264 @ 0000013f85b22440] Loaded sym: cuvidCtxLockCreate
[h264 @ 0000013f85b22440] Loaded sym: cuvidCtxLockDestroy
[h264 @ 0000013f85b22440] Loaded sym: cuvidCtxLock
[h264 @ 0000013f85b22440] Loaded sym: cuvidCtxUnlock
[h264 @ 0000013f85b22440] Loaded sym: cuvidCreateVideoSource
[h264 @ 0000013f85b22440] Loaded sym: cuvidCreateVideoSourceW
[h264 @ 0000013f85b22440] Loaded sym: cuvidDestroyVideoSource
[h264 @ 0000013f85b22440] Loaded sym: cuvidSetVideoSourceState
[h264 @ 0000013f85b22440] Loaded sym: cuvidGetVideoSourceState
[h264 @ 0000013f85b22440] Loaded sym: cuvidGetSourceVideoFormat
[h264 @ 0000013f85b22440] Loaded sym: cuvidGetSourceAudioFormat
[h264 @ 0000013f85b22440] Loaded sym: cuvidCreateVideoParser
[h264 @ 0000013f85b22440] Loaded sym: cuvidParseVideoData
[h264 @ 0000013f85b22440] Loaded sym: cuvidDestroyVideoParser
[h264 @ 0000013f85b22440] NVDEC capabilities:
[h264 @ 0000013f85b22440] format supported: yes, max_mb_count: 65536
[h264 @ 0000013f85b22440] min_width: 48, max_width: 4096
[h264 @ 0000013f85b22440] min_height: 16, max_height: 4096
[h264 @ 0000013f85bd04c0] nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
[h264 @ 0000013f1cec7580] nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
[h264 @ 0000013f6efb0f40] nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2

I've attached the most important code snippet to this mail. Hope it will help.



>Среда, 17 апреля 2019, 12:21 +03:00 от Hristo Ivanov <hivanov.ffmailing at gmail.com>:
>
>Hi.
>
>> Is it because of NVIDIA GPUs have concurrent session limitation?
>
>There is a session limitation for encoding for sure, but I think there is no such thing for decoding:
>https://developer.nvidia.com/video-encode-decode-gpu-support-matrix
>
>> By the way, I don't understand where these messages are come from. They are just printed in my console.
>
>Those messages are from the ffmpeg log. The ffmpeg code is full with calls to 'av_log(void *avcl, int level, const char *fmt, ....)'.
>Depending on the loglevel in use the messages are printed or ignored.
>For the ffmpeg tool the '-loglevel' flag can be used to configure what messages should be printed and what messages should not.
>With the C-API, the ' av_log_set_level(int level)' function can be used to configure the log level.
>The different log levels can be seen here:
>
>https://ffmpeg.org/doxygen/trunk/group__lavu__log__constants.html  
>
>Running your program with log level verbose or maybe even debug could give you some clue to why the creation of the 6th decoder fails.
>
>Are the video streams 4K? My guest is you are running out of memory on the GPU.
>
>Regards.
>_______________________________________________
>Libav-user mailing list
>Libav-user at ffmpeg.org
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>
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-- 
С уважением, Ахмед Анам.
Best regards, Akhmed Anam.
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