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• multiple GPU encoding use FFMPEG under multiple threads environment

  8 septembre 2022, par shenuo

  Here is the application situation.
I want use 4 NV GPUs to carry out some calculation work (CUDA based), and encoding work (FFMPEG &NVEC), it works fine when they are in serial. But when I want them to be parallel. like this

  


  void encodingwork(){
            #pragma omp parallel for num_threads(4)
                for (int i = 0; i < 4; i++) {
                    cudaSetDevice(i);
                    encodingwork();
                }
        }

        int main(){
            thread thd;
            for (int k = 0; k < N; k++) {
#pragma omp parallel for num_threads(4)
                for (int i = 0; i < 4; i++) {
                    cudaSetDevice(i);
                    cudawork();
                }
                if (k != 0)
                    thd.join();
                thd = thread(encodingwork);
            }
            thd.join();
        }


  


  an error will be thrown out from ffmpeg. just like

  


  [AVHWDeviceContext @ 000002334959ac80] cu->cuMemFree((CUdeviceptr)data) failed -> CUDA_ERROR_ILLEGAL_ADDRESS: an illegal memory access was encountered

[hevc_nvenc @ 00000230c956b200] EncodePicture failed!: generic error (20):
Error sending a frame for encoding: -1313558101 (Unknown error occurred)


  


  can anybody tell me what's wrong with this ?

  


• Encode Ogg/Opus with very specific structure

  28 septembre 2022, par sonovice

  I have an ogg/opus file with a pretty special structure that I would like to reproduce.

  


  opusinfo returns a few hints of how it was made :

  


  New logical stream (#1, serial: 59d24a85): type opus
Encoded with Lavf56.40.101
User comments section follows...
        encoder=Lavc56.60.100 libopus
        encoder_options=--quiet --bitrate 96 --vbr
        pad=00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Opus stream 1:
        Pre-skip: 312
        Playback gain: 0 dB
        Channels: 2
        Original sample rate: 48000Hz
        Packet duration:   60.0ms (max),   56.6ms (avg),   20.0ms (min)
        Page duration:   1460.0ms (max),  323.6ms (avg),  120.0ms (min)
        Total data length: 38872802 bytes (overhead: 1.12%)
        Playback length: 51m:11.473s
        Average bitrate: 101.2 kb/s, w/o overhead: 100.1 kb/s
Logical stream 1 ended


  


  Lavf/Lavc suggests that it was made with FFMPEG, but I am not able to find suitable settings.

  


  Looking at the actual bytes, it starts with an 0x200 (512) byte long ogg page containing metadata, followed by an 0xE00 (3584) byte long ogg page with actual audio content. Both pages sum up exactly to 0x1000 (4096) bytes.


  


  After that, each page is exactly 0x1000 (4096) bytes long with potential zero padding, so that the pages start at offsets 0x1000, 0x2000, 0x3000 etc.


  


  Is there any known tool or library that can produce such ogg/opus files from PCM wave audio ?

  


  (Unfortunately I cannot share the file as it contains proprietary content.)

  


• Integrate necessary ffmpeg libraries in own project for MCU (microcontrolers) [closed]

  16 septembre 2023, par Borel Kamnang

  I use two ffmpeg commands here :

  


  ffmpeg -i BigBuckBunny_320x180.mp4 -vf scale=192:96,setsar=1:1 outputBBB.mp4
ffmpeg -i outputBBB.mp4 -vf "fps=12,scale=-1:96:flags=lanczos,crop=192:in_h:(in_w-192)/2:0" -c:v rawvideo -pix_fmt rgb565be BigBuckBunny_192x96_12fps.rgb


  


  The first is to downscale an original video and the second is to convert the scaled video to a .rgb format.

  


  As anew user of ffmpeg, I would like to know what are libraries used for that two command to just integrate them in my Arduino IDE C++ project an just call the necessary functions to do the downscale and the conversion.

  


  And another of my concerns is knowing how I can run any ffmpeg in an Raspberry Pi Pico W (RP2040) or ESP32 microcontroller ?

  


  I tried to include the ffmpeg libraries folder in a created Arduino IDE project for Raspberry pico w and the link for files doesn't work. In addition to having the config.h and config components.h files missing in the folder downloaded from the ffmpeg site, there are too many dependencies between .h and .c files.

  


  extern "C" {
  #include "src/ffmpeg/libavcodec/avcodec.h"       
  #include "src/ffmpeg/libavutil/mathematics.h"
}
void setup() {
   Serial.begin(115200);
   delay(10000);
 }
 loop(){
 }


  


  It's been three days today that I've been trying to compile from Arduino IDE, and correct the links in the files.
The problem is also that I don't even have the certainty of what it will work in the Raspberry Pi PicoW or ESP32 afterwards.