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• Encoding audio_common messages to OPUS

  14 juin 2023, par djangbahevans

  ---

  


  I am trying to stream microphone and camera data to Amazon KVS WebRTC. I'm able to make video work using this package (adapted for noetic) however I am struggling to make audio work. I'm using the audio_capture package to get mp3 frames. I'm trying to convert this to OPUS frames before streaming to KVS, but I'm unsure how to do this. I wrote this bit of code based on the small resources I can find on using ffmpeg, but it's not working. avcodec_fill_audio_frame is returning -22.

  


  #include "opus_encoder.h"

OPUSEncoder::OPUSEncoder() {
  av_register_all();
  codecContext == nullptr;
}

OPUSEncoder::~OPUSEncoder() {
  if (codecContext != nullptr) {
    avcodec_free_context(&codecContext);
  }
}

int OPUSEncoder::Initialize(int Fs, int channels) {
  AVCodec *codec = avcodec_find_encoder(AV_CODEC_ID_OPUS);
  if (!codec) {
    printf("Codec not found\n");
    return -1;
  }

  codecContext = avcodec_alloc_context3(codec);
  if (!codecContext) {
    printf("Could not allocate audio codec context\n");
    return -1;
  }

  codecContext->sample_fmt = AV_SAMPLE_FMT_S16;
  codecContext->bit_rate = 128000;
  codecContext->sample_rate = Fs;
  codecContext->channel_layout = av_get_default_channel_layout(channels);
  codecContext->channels = channels;

  if (avcodec_open2(codecContext, codec, nullptr) < 0) {
    printf("Could not open codec\n");
    return -1;
  }

  return 0;
}

int OPUSEncoder::Encode(const uint8_t *audio_data, int frameSize,
                        uint8_t *out) {
  AVPacket pkt;
  av_init_packet(&pkt);
  pkt.data = nullptr;
  pkt.size = 0;

  AVFrame *frame = av_frame_alloc();
  frame->nb_samples = frameSize;
  frame->format = codecContext->sample_fmt;
  frame->channel_layout = codecContext->channel_layout;

  int ret = avcodec_fill_audio_frame(frame, codecContext->channels,
                                     codecContext->sample_fmt, audio_data,
                                     frameSize * 2, 0);
  if (ret < 0) {
    printf("Error filling audio frame: %d\n", ret);
    return -1;
  }

  ret = avcodec_send_frame(codecContext, frame);
  if (ret < 0) {
    printf("Error sending the frame to the encoder\n");
    return -1;
  }

  while (ret >= 0) {
    ret = avcodec_receive_packet(codecContext, &pkt);
    if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
      return 0;
    } else if (ret < 0) {
      printf("Error encoding audio frame\n");
      return -1;
    }

    memcpy(out, pkt.data, pkt.size);
    out += pkt.size;
    av_packet_unref(&pkt);
  }

  av_frame_free(&frame);

  return 0;
}


  


• FFmpeg recorded video is dark with Xvfb and chrome headless on Centos 7

  15 juin 2023, par narsy4

  I am trying to do a video recording of headless chrome session on Centos 7 (Amazon EC2 instance) using ffmpeg. I have installed ffmpeg, Xvfb and google chrome on the machine. I started Xvfb on :99, verified the display using xdpyinfo and started chrome. However when I run the ffmpeg cmd to capture the video (no errors in ffmpeg debug logs), the output is dark with a X sign in the centre of video screen. What am I doing wrong here ? Any help is appreciated.

  


  **Xvfb and chrome commands**
Xvfb :99 -screen 0 1920x1080x24 &
export DISPLAY=:99
google-chrome --headless --disable-gpu --no-sandbox --start-maximized --window-size=1920x1080 https://www.google.com



  


  **FFmpeg command**
ffmpeg -video_size 1920x1080 -framerate 30 -f x11grab -i :99 -loglevel debug -pix_fmt yuv420p /tmp/video.mp4



  


  dark video

  


  Searched for and read a few threads on this, but couldn't get it to work.

  


• Installing FFMPEG on my EC2 instance takes too long ; what am I doing wrong ? [closed]

  24 août 2023, par Shaban Khawar

  I found a good article on how to download onto my EC2 instance : link
Here's the issue. It takes forever ! It takes around 15 minutes to install.

  


  I'm running my EC2 instance on Amazon Linux 2023, so no apt-get for me.
Also my EC2 instance is created by my EB environment, so if auto-scaling occurs, my instance will be terminated and a new one will be created. I can set .ebextensions to run all the commands to install FFMPEG again but as mentioned above, it takes forever ! That means for 15-20 minutes, my server is down because of one dependancy. I feel like I'm going about this the wrong way, so any advice is appreciated.