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• Create movie programatically with ffmpeg

  16 janvier 2019, par Martin Delille

  I would like to create a movie programatically with ffmpeg.

  Here is my code :

  QString fileName = "test.mov";
  
  static char errorString[AV_ERROR_MAX_STRING_SIZE];
  
  
  
  printf("Video encoding\n");
  
  
  
  AVOutputFormat *outputFormat = av_guess_format(nullptr, fileName.toStdString().c_str(), nullptr);
  
  
  
  if (outputFormat == nullptr) {
  
      qDebug() << "Could not find suitable format for" << fileName;
  
      return false;
  
  }
  
  
  
  enum AVCodecID codec_id = AV_CODEC_ID_MJPEG;
  
  
  
  qDebug() << "Format Name:" << outputFormat->name;
  
  qDebug() << "Format Video Codec:" << outputFormat->video_codec;
  
  outputFormat->video_codec = codec_id;
  
  
  
  /// allocate the output media context, formatContext
  
  AVFormatContext *formatContext = avformat_alloc_context();
  
  formatContext->oformat = outputFormat;
  
  
  
  // find the mpeg1 video encoder
  
  AVCodec *codec = avcodec_find_encoder(codec_id);
  
  
  
  if (!codec) {
  
      qDebug() << "codec not found";
  
      return false;
  
  }
  
  
  
  qDebug() << "Codec name:" << codec->name;
  
  
  
  AVStream *videoStream = avformat_new_stream(formatContext, codec);
  
  // put sample parameters
  
  videoStream->codecpar->bit_rate = 400000;
  
  videoStream->codecpar->width = width;
  
  videoStream->codecpar->height = height;
  
  videoStream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
  
  videoStream->codecpar->format = AV_PIX_FMT_YUVJ422P;
  
  videoStream->time_base.num = 1;
  
  videoStream->time_base.den = 25;
  
  
  
  AVCodecContext *codecContext = avcodec_alloc_context3(nullptr);
  
  codecContext->codec_id = codec_id;
  
  codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
  
  codecContext->width = width;
  
  codecContext->height = height;
  
  codecContext->time_base.num = 1;
  
  codecContext->time_base.den = 25;
  
  codecContext->pix_fmt = AV_PIX_FMT_YUVJ422P;
  
  
  
  if (int error = avcodec_parameters_to_context(codecContext, videoStream->codecpar)) {
  
      qDebug() << "Error parameting the context:" << av_make_error_string(errorString, AV_ERROR_MAX_STRING_SIZE, error);
  
      return false;
  
  }
  
  
  
  // open it
  
  if (int error = avcodec_open2(codecContext, codec, nullptr)) {
  
      qDebug() << "Could not open codec:" << av_make_error_string(errorString, AV_ERROR_MAX_STRING_SIZE, error);
  
      return false;
  
  }
  
  
  
  // alloc image and output buffer
  
  AVFrame *frame = av_frame_alloc();
  
  frame->format = codecContext->pix_fmt;
  
  frame->width = codecContext->width;
  
  frame->height = codecContext->height;
  
  
  
  if (int error = av_image_alloc(frame->data, frame->linesize, frame->width, frame->height, static_cast<enum avpixelformat="avpixelformat">(frame->format), 0)) {
  
      qDebug() &lt;&lt; "Error allocating image data:" &lt;&lt; av_make_error_string(errorString, AV_ERROR_MAX_STRING_SIZE, error);
  
      return false;
  
  }
  
  
  
  // Open the output file, if needed
  
  if (!(outputFormat->flags &amp; AVFMT_NOFILE)) {
  
      if (avio_open(&amp;formatContext->pb, fileName.toStdString().c_str(), AVIO_FLAG_WRITE) &lt; 0) {
  
          qDebug() &lt;&lt; "Could not open" &lt;&lt; fileName;
  
          return false;
  
      }
  
  }
  
  
  
  // some formats want stream headers to be separate
  
  if (formatContext->oformat->flags &amp; AVFMT_GLOBALHEADER) {
  
      codecContext->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  }
  
  
  
  if (int error = avformat_write_header(formatContext, nullptr)) {
  
      qDebug() &lt;&lt; "error writing header:" &lt;&lt; av_make_error_string(errorString, AV_ERROR_MAX_STRING_SIZE, error);
  
      return false;
  
  }
  
  </enum>

  Unfortunately, when I execute it I have the following output :

  Format Name: mov
  
  Format Video Codec: 27
  
  Codec name: mjpeg
  
  [mov @ 0x1048c7000] Could not find tag for codec none in stream #0, codec not currently supported in container
  
  error writing header: Invalid argument

  What am I doing wrong ?

• Live555 truncates encoded data of FFMpeg

  22 novembre 2019, par Harshil Makwana

  I am trying to stream H264 based data using Live555 over RTSP.

  I am capturing data using V4L2, and then encodes it using FFMPEG and then passing data to Live555’s DeviceSource file, in that I using H264VideoStreamFramer class,

  Below is my codec settings to configure AVCodecContext of encoder,

  codec = avcodec_find_encoder_by_name(CODEC_NAME);
  
  if (!codec) {
  
      cerr << "Codec " << codec_name << " not found\n";
  
      exit(1);
  
  }
  
  
  
  c = avcodec_alloc_context3(codec);
  
  if (!c) {
  
      cerr << "Could not allocate video codec context\n";
  
      exit(1);
  
  }
  
  
  
  pkt = av_packet_alloc();
  
  if (!pkt)
  
      exit(1);
  
  
  
  /* put sample parameters */
  
  c->bit_rate = 400000;
  
  /* resolution must be a multiple of two */
  
  c->width = PIC_HEIGHT;
  
  c->height = PIC_WIDTH;
  
  /* frames per second */
  
  c->time_base = (AVRational){1, FPS};
  
  c->framerate = (AVRational){FPS, 1};
  
  c->gop_size = 10;
  
  c->max_b_frames = 1;
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  c->rtp_payload_size = 30000;
  
  if (codec->id == AV_CODEC_ID_H264)
  
      av_opt_set(c->priv_data, "preset", "fast", 0);
  
  av_opt_set_int(c->priv_data, "slice-max-size", 30000, 0);
  
  /* open it */
  
  ret = avcodec_open2(c, codec, NULL);
  
  if (ret < 0) {
  
      cerr << "Could not open codec\n";
  
      exit(1);
  
  }

  And I am getting encoded data using avcodec_receive_packet() function. which will return AVPacket.

  And I am passing AVPacket’s data into DeviceSource file below is code snippet of my Live555 code :

  void DeviceSource::deliverFrame() {
  
      if (!isCurrentlyAwaitingData()) return; // we're not ready for the data yet
  
  
  
      u_int8_t* newFrameDataStart = (u_int8_t*) pkt->data;
  
      unsigned newFrameSize = pkt->size; //%%% TO BE WRITTEN %%%
  
      // Deliver the data here:
  
      if (newFrameSize > fMaxSize) { // Condition becomes true many times
  
          fFrameSize = fMaxSize;
  
          fNumTruncatedBytes = newFrameSize - fMaxSize;
  
      } else {
  
          fFrameSize = newFrameSize;
  
      }
  
      gettimeofday(&fPresentationTime, NULL); // If you have a more accurate time - e.g., from an encoder - then use that instead.
  
      // If the device is *not* a 'live source' (e.g., it comes instead from a file or buffer), then set "fDurationInMicroseconds" here.
  
      memmove(fTo, newFrameDataStart, fFrameSize);
  
  }

  But here, sometimes my packet’s size is getting more than fMaxSize value and as per LIVE555 logic it will truncate frame data, so that sometimes I am getting bad frames on my VLC,

  From Live555 forum, I get to know that encoder should not send packet whose size is more than fMaxSize value, so my question is :

  How to restrict encoder to limit size of packet ?

  Thanks in Advance,

  Harshil

• Command Line 'hls_segment_size' creates TS files with segment failures

  14 octobre 2019, par Phantom

  I am converting a simple mp4 video to hls but I need the segments to be in approximately a specific size

  I researched and found :

  -hls_segment_size 17000000

  17000000 bytes( 17MB)

  This creates TS files with approximate sizes, (does not have to be exact size)

  ffmpeg.exe -i "in.mp4" -vcodec copy -acodec aac -hls_list_size 0 -hls_segment_size 17000000 -f hls "out.m3u8"

  In the m3u8 file is created ’#EXT-X-BYTERANGE’, which is the way I want it

  #EXTM3U
  
  #EXT-X-VERSION:4
  
  #EXT-X-TARGETDURATION:10
  
  #EXT-X-MEDIA-SEQUENCE:0
  
  #EXTINF:8.400000,
  
  #EXT-X-BYTERANGE:1662108@0
  
  SampleVideo_1280x720_30mb0.ts
  
  #EXTINF:4.560000,
  
  #EXT-X-BYTERANGE:383896@0
  
  SampleVideo_1280x720_30mb1.ts
  
  #EXTINF:3.120000,
  
  #EXT-X-BYTERANGE:408712@383896
  
  SampleVideo_1280x720_30mb1.ts
  
  #EXTINF:5.640000,
  
  #EXT-X-BYTERANGE:1161840@0
  
  SampleVideo_1280x720_30mb2.ts
  
  #EXTINF:1.880000,
  
  #EXT-X-BYTERANGE:230864@0
  
  SampleVideo_1280x720_30mb3.ts
  
  #EXTINF:2.160000,
  
  #EXT-X-BYTERANGE:330880@230864
  
  SampleVideo_1280x720_30mb3.ts
  
  #EXTINF:2.080000,
  
  #EXT-X-BYTERANGE:489928@0
  
  SampleVideo_1280x720_30mb4.ts
  
  #EXTINF:4.400000,
  
  #EXT-X-BYTERANGE:1564348@489928
  
  SampleVideo_1280x720_30mb4.ts
  
  ...

  It seems alright, but it has a little problem. I’m testing on a player in the browser, and when the seconds goes from one segment to the other the video has a lock in sound and video. Something very annoying, not natural in the video.

  Not using ’-hls_segment_size’ will have functional TS files, and without BYTERANGE in the m3u8 file

  However, the size of the TS file will be according to the seconds defined

  I am currently trying to get a ts file that is close to a size set between 15MB and 20MB, and have BYTERANGE in the m3u8 file.

  Does anyone have any ideas ?

  here’s the problem I’m trying to describe :

  http://phantsc.rf.gd/AAA/Bbb.html

  exactly in the second 7 of the video a ’locking’ happens, this happens when going from one segment to another