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• Will ffmpeg slow down my server ? [on hold]

  12 novembre 2015, par Akash Bose

  I am trying to build a social network where people can upload their mp3 audio files and I want those files to convert to lower bit rate on the fly with ffmpeg.

  Will it slow down my server if I have minimum amount of good traffic ?

  And it would be great if you can tell what server configuration do i need for this kind of setup ?

• RTSP relay using ffmpeg library

  23 novembre 2015, par kiran_g

  I am implementing an RTSP relay using libavcodec (ffmpeg). Basically, it connects to an IP camera, which is an RTSP server, PULLs the stream and then PUSHes it to wowza. I am finding it very difficult to get any sample implementation for this in the internet. So I started implementing this using bits and pieces from here and there. I took code for code samples to a) read RTSP stream and write to file b)read from file and serve it over RTSP.

  This is the current state of the code :

  /*
  
   * Copyright (c) 2010 Nicolas George
  
   * Copyright (c) 2011 Stefano Sabatini
  
   * Copyright (c) 2014 Andrey Utkin
  
   *
  
   * Permission is hereby granted, free of charge, to any person obtaining a copy
  
   * of this software and associated documentation files (the "Software"), to deal
  
   * in the Software without restriction, including without limitation the rights
  
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  
   * copies of the Software, and to permit persons to whom the Software is
  
   * furnished to do so, subject to the following conditions:
  
   *
  
   * The above copyright notice and this permission notice shall be included in
  
   * all copies or substantial portions of the Software.
  
   *
  
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  
   * THE SOFTWARE.
  
   */
  
  
  
  /**
  
   * @file
  
   * API example for demuxing, decoding, filtering, encoding and muxing
  
   * @example transcoding.c
  
   */
  
  
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libavfilter></libavfilter>avfiltergraph.h>
  
  #include <libavfilter></libavfilter>buffersink.h>
  
  #include <libavfilter></libavfilter>buffersrc.h>
  
  #include <libavutil></libavutil>opt.h>
  
  #include <libavutil></libavutil>pixdesc.h>
  
  
  
  static AVFormatContext *ifmt_ctx,*temp;
  
  static AVFormatContext *ofmt_ctx;
  
  typedef struct FilteringContext {
  
      AVFilterContext *buffersink_ctx;
  
      AVFilterContext *buffersrc_ctx;
  
      AVFilterGraph *filter_graph;
  
  } FilteringContext;
  
  static FilteringContext *filter_ctx;
  
  
  
  static int open_input_file(const char *filename)
  
  {
  
      int ret;
  
      unsigned int i;
  
  
  
      ifmt_ctx = NULL;
  
      if ((ret = avformat_open_input(&amp;ifmt_ctx, filename, NULL, NULL)) &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
  
          return ret;
  
      }
  
  
  
      if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
  
          return ret;
  
      }
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          AVStream *stream;
  
          AVCodecContext *codec_ctx;
  
          stream = ifmt_ctx->streams[i];
  
          codec_ctx = stream->codec;
  
          /* Reencode video &amp; audio and remux subtitles etc. */
  
          if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
  
                  || codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
              /* Open decoder */
  
              ret = avcodec_open2(codec_ctx,
  
                      avcodec_find_decoder(codec_ctx->codec_id), NULL);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
          }
  
      }
  
  
  
      av_dump_format(ifmt_ctx, 0, filename, 0);
  
      return 0;
  
  }
  
  
  
  static int open_output_file(const char *filename)
  
  {
  
      AVStream *out_stream;
  
      AVStream *in_stream;
  
      AVCodecContext *dec_ctx, *enc_ctx;
  
      AVCodec *encoder,*codec;
  
      int ret;
  
      unsigned int i;
  
  
  
      ofmt_ctx = NULL;
  
      avformat_open_input(&amp;temp, "rtsp://localhost:8554/live", NULL, NULL);
  
      avformat_alloc_output_context2(&amp;ofmt_ctx, temp->oformat,"rtsp", filename);
  
      if (!ofmt_ctx) {
  
          av_log(NULL, AV_LOG_ERROR, "Could not create output context\n");
  
          return AVERROR_UNKNOWN;
  
      }
  
  
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          out_stream = avformat_new_stream(ofmt_ctx, NULL);
  
          if (!out_stream) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n");
  
              return AVERROR_UNKNOWN;
  
          }
  
  
  
          in_stream = ifmt_ctx->streams[i];
  
          dec_ctx = in_stream->codec;
  
          enc_ctx = out_stream->codec;
  
  
  
          if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
  
                  || dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
              /* in this example, we choose transcoding to same codec */
  
              encoder = avcodec_find_encoder(dec_ctx->codec_id);
  
              printf("codec : %d",dec_ctx->codec_id);
  
              if (!encoder) {
  
                  av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
  
                  return AVERROR_INVALIDDATA;
  
              }
  
  
  
              /* In this example, we transcode to same properties (picture size,
  
               * sample rate etc.). These properties can be changed for output
  
               * streams easily using filters */
  
              if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
  
                  enc_ctx->height = dec_ctx->height;
  
                  enc_ctx->width = dec_ctx->width;
  
                  enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
  
                  /* take first format from list of supported formats */
  
                  enc_ctx->pix_fmt = encoder->pix_fmts[0];
  
                  //enc_ctx->codec_id = AV_CODEC_ID_H264;
  
                  /* video time_base can be set to whatever is handy and supported by encoder */
  
                  enc_ctx->time_base = dec_ctx->time_base;
  
              } else {
  
                  enc_ctx->sample_rate = dec_ctx->sample_rate;
  
                  enc_ctx->channel_layout = dec_ctx->channel_layout;
  
                  enc_ctx->channels = av_get_channel_layout_nb_channels(enc_ctx->channel_layout);
  
                  /* take first format from list of supported formats */
  
                  enc_ctx->sample_fmt = encoder->sample_fmts[0];
  
                  enc_ctx->pix_fmt =AV_PIX_FMT_RGB24 ;
  
                  enc_ctx->time_base = (AVRational){1, enc_ctx->sample_rate};
  
              }
  
  
  
              /* Third parameter can be used to pass settings to encoder */
  
              //codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
              ret = avcodec_open2(enc_ctx, encoder, NULL);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
          } else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) {
  
              av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i);
  
              return AVERROR_INVALIDDATA;
  
          } else {
  
              /* if this stream must be remuxed */
  
              ret = avcodec_copy_context(ofmt_ctx->streams[i]->codec,
  
                      ifmt_ctx->streams[i]->codec);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Copying stream context failed\n");
  
                  return ret;
  
              }
  
          }
  
  
  
          if (ofmt_ctx->oformat->flags &amp; AVFMT_GLOBALHEADER)
  
              enc_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      }
  
      av_dump_format(ofmt_ctx, 0, filename, 1);
  
  
  
      if (!(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE)) {
  
          ret = avio_open(&amp;ofmt_ctx->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Could not open output file '%s'", filename);
  
              return ret;
  
          }
  
      }
  
  
  
      /* init muxer, write output file header */
  
      ret = avformat_write_header(ofmt_ctx, NULL);
  
      if (ret &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n");
  
          return ret;
  
      }
  
  
  
      return 0;
  
  }
  
  
  
  static int init_filter(FilteringContext* fctx, AVCodecContext *dec_ctx,
  
          AVCodecContext *enc_ctx, const char *filter_spec)
  
  {
  
      char args[512];
  
      int ret = 0;
  
      AVFilter *buffersrc = NULL;
  
      AVFilter *buffersink = NULL;
  
      AVFilterContext *buffersrc_ctx = NULL;
  
      AVFilterContext *buffersink_ctx = NULL;
  
      AVFilterInOut *outputs = avfilter_inout_alloc();
  
      AVFilterInOut *inputs  = avfilter_inout_alloc();
  
      AVFilterGraph *filter_graph = avfilter_graph_alloc();
  
  
  
      if (!outputs || !inputs || !filter_graph) {
  
          ret = AVERROR(ENOMEM);
  
          goto end;
  
      }
  
  
  
      if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
  
          buffersrc = avfilter_get_by_name("buffer");
  
          buffersink = avfilter_get_by_name("buffersink");
  
          if (!buffersrc || !buffersink) {
  
              av_log(NULL, AV_LOG_ERROR, "filtering source or sink element not found\n");
  
              ret = AVERROR_UNKNOWN;
  
              goto end;
  
          }
  
  
  
          snprintf(args, sizeof(args),
  
                  "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
  
                  dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
  
                  dec_ctx->time_base.num, dec_ctx->time_base.den,
  
                  dec_ctx->sample_aspect_ratio.num,
  
                  dec_ctx->sample_aspect_ratio.den);
  
  
  
          ret = avfilter_graph_create_filter(&amp;buffersrc_ctx, buffersrc, "in",
  
                  args, NULL, filter_graph);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source\n");
  
              goto end;
  
          }
  
  
  
          ret = avfilter_graph_create_filter(&amp;buffersink_ctx, buffersink, "out",
  
                  NULL, NULL, filter_graph);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");
  
              goto end;
  
          }
  
  
  
          ret = av_opt_set_bin(buffersink_ctx, "pix_fmts",
  
                  (uint8_t*)&amp;enc_ctx->pix_fmt, sizeof(enc_ctx->pix_fmt),
  
                  AV_OPT_SEARCH_CHILDREN);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format\n");
  
              goto end;
  
          }
  
      } else if (dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
          buffersrc = avfilter_get_by_name("abuffer");
  
          buffersink = avfilter_get_by_name("abuffersink");
  
          if (!buffersrc || !buffersink) {
  
              av_log(NULL, AV_LOG_ERROR, "filtering source or sink element not found\n");
  
              ret = AVERROR_UNKNOWN;
  
              goto end;
  
          }
  
  
  
          if (!dec_ctx->channel_layout)
  
              dec_ctx->channel_layout =
  
                  av_get_default_channel_layout(dec_ctx->channels);
  
          snprintf(args, sizeof(args),
  
                  "time_base=%d/%d:sample_rate=%d:sample_fmt=%s:channel_layout=0x%"PRIx64,
  
                  dec_ctx->time_base.num, dec_ctx->time_base.den, dec_ctx->sample_rate,
  
                  av_get_sample_fmt_name(dec_ctx->sample_fmt),
  
                  dec_ctx->channel_layout);
  
          ret = avfilter_graph_create_filter(&amp;buffersrc_ctx, buffersrc, "in",
  
                  args, NULL, filter_graph);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer source\n");
  
              goto end;
  
          }
  
  
  
          ret = avfilter_graph_create_filter(&amp;buffersink_ctx, buffersink, "out",
  
                  NULL, NULL, filter_graph);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot create audio buffer sink\n");
  
              goto end;
  
          }
  
  
  
          ret = av_opt_set_bin(buffersink_ctx, "sample_fmts",
  
                  (uint8_t*)&amp;enc_ctx->sample_fmt, sizeof(enc_ctx->sample_fmt),
  
                  AV_OPT_SEARCH_CHILDREN);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot set output sample format\n");
  
              goto end;
  
          }
  
  
  
          ret = av_opt_set_bin(buffersink_ctx, "channel_layouts",
  
                  (uint8_t*)&amp;enc_ctx->channel_layout,
  
                  sizeof(enc_ctx->channel_layout), AV_OPT_SEARCH_CHILDREN);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot set output channel layout\n");
  
              goto end;
  
          }
  
  
  
          ret = av_opt_set_bin(buffersink_ctx, "sample_rates",
  
                  (uint8_t*)&amp;enc_ctx->sample_rate, sizeof(enc_ctx->sample_rate),
  
                  AV_OPT_SEARCH_CHILDREN);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot set output sample rate\n");
  
              goto end;
  
          }
  
      } else {
  
          ret = AVERROR_UNKNOWN;
  
          goto end;
  
      }
  
  
  
      /* Endpoints for the filter graph. */
  
      outputs->name       = av_strdup("in");
  
      outputs->filter_ctx = buffersrc_ctx;
  
      outputs->pad_idx    = 0;
  
      outputs->next       = NULL;
  
  
  
      inputs->name       = av_strdup("out");
  
      inputs->filter_ctx = buffersink_ctx;
  
      inputs->pad_idx    = 0;
  
      inputs->next       = NULL;
  
  
  
      if (!outputs->name || !inputs->name) {
  
          ret = AVERROR(ENOMEM);
  
          goto end;
  
      }
  
  
  
      if ((ret = avfilter_graph_parse_ptr(filter_graph, filter_spec,
  
                      &amp;inputs, &amp;outputs, NULL)) &lt; 0)
  
          goto end;
  
  
  
      if ((ret = avfilter_graph_config(filter_graph, NULL)) &lt; 0)
  
          goto end;
  
  
  
      /* Fill FilteringContext */
  
      fctx->buffersrc_ctx = buffersrc_ctx;
  
      fctx->buffersink_ctx = buffersink_ctx;
  
      fctx->filter_graph = filter_graph;
  
  
  
  end:
  
      avfilter_inout_free(&amp;inputs);
  
      avfilter_inout_free(&amp;outputs);
  
  
  
      return ret;
  
  }
  
  
  
  static int init_filters(void)
  
  {
  
      const char *filter_spec;
  
      unsigned int i;
  
      int ret;
  
      filter_ctx = av_malloc_array(ifmt_ctx->nb_streams, sizeof(*filter_ctx));
  
      if (!filter_ctx)
  
          return AVERROR(ENOMEM);
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          filter_ctx[i].buffersrc_ctx  = NULL;
  
          filter_ctx[i].buffersink_ctx = NULL;
  
          filter_ctx[i].filter_graph   = NULL;
  
          if (!(ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO
  
                  || ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO))
  
              continue;
  
  
  
  
  
          if (ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
  
              filter_spec = "null"; /* passthrough (dummy) filter for video */
  
          else
  
              filter_spec = "anull"; /* passthrough (dummy) filter for audio */
  
          ret = init_filter(&amp;filter_ctx[i], ifmt_ctx->streams[i]->codec,
  
                  ofmt_ctx->streams[i]->codec, filter_spec);
  
          if (ret)
  
              return ret;
  
      }
  
      return 0;
  
  }
  
  
  
  static int encode_write_frame(AVFrame *filt_frame, unsigned int stream_index, int *got_frame) {
  
      int ret;
  
      int got_frame_local;
  
      AVPacket enc_pkt;
  
      int (*enc_func)(AVCodecContext *, AVPacket *, const AVFrame *, int *) =
  
          (ifmt_ctx->streams[stream_index]->codec->codec_type ==
  
           AVMEDIA_TYPE_VIDEO) ? avcodec_encode_video2 : avcodec_encode_audio2;
  
  
  
      if (!got_frame)
  
          got_frame = &amp;got_frame_local;
  
  
  
      av_log(NULL, AV_LOG_INFO, "Encoding frame\n");
  
      /* encode filtered frame */
  
      enc_pkt.data = NULL;
  
      enc_pkt.size = 0;
  
      av_init_packet(&amp;enc_pkt);
  
      ret = enc_func(ofmt_ctx->streams[stream_index]->codec, &amp;enc_pkt,
  
              filt_frame, got_frame);
  
      av_frame_free(&amp;filt_frame);
  
      if (ret &lt; 0)
  
          return ret;
  
      if (!(*got_frame))
  
          return 0;
  
  
  
      /* prepare packet for muxing */
  
      enc_pkt.stream_index = stream_index;
  
      av_packet_rescale_ts(&amp;enc_pkt,
  
                           ofmt_ctx->streams[stream_index]->codec->time_base,
  
                           ofmt_ctx->streams[stream_index]->time_base);
  
  
  
      av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n");
  
      /* mux encoded frame */
  
      ret = av_interleaved_write_frame(ofmt_ctx, &amp;enc_pkt);
  
      return ret;
  
  }
  
  
  
  static int filter_encode_write_frame(AVFrame *frame, unsigned int stream_index)
  
  {
  
      int ret;
  
      AVFrame *filt_frame;
  
  
  
      av_log(NULL, AV_LOG_INFO, "Pushing decoded frame to filters\n");
  
      /* push the decoded frame into the filtergraph */
  
      ret = av_buffersrc_add_frame_flags(filter_ctx[stream_index].buffersrc_ctx,
  
              frame, 0);
  
      if (ret &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Error while feeding the filtergraph\n");
  
          return ret;
  
      }
  
  
  
      /* pull filtered frames from the filtergraph */
  
      while (1) {
  
          filt_frame = av_frame_alloc();
  
          if (!filt_frame) {
  
              ret = AVERROR(ENOMEM);
  
              break;
  
          }
  
          av_log(NULL, AV_LOG_INFO, "Pulling filtered frame from filters\n");
  
          ret = av_buffersink_get_frame(filter_ctx[stream_index].buffersink_ctx,
  
                  filt_frame);
  
          if (ret &lt; 0) {
  
              /* if no more frames for output - returns AVERROR(EAGAIN)
  
               * if flushed and no more frames for output - returns AVERROR_EOF
  
               * rewrite retcode to 0 to show it as normal procedure completion
  
               */
  
              if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
  
                  ret = 0;
  
              av_frame_free(&amp;filt_frame);
  
              break;
  
          }
  
  
  
          filt_frame->pict_type = AV_PICTURE_TYPE_NONE;
  
          ret = encode_write_frame(filt_frame, stream_index, NULL);
  
          if (ret &lt; 0)
  
              break;
  
      }
  
  
  
      return ret;
  
  }
  
  
  
  static int flush_encoder(unsigned int stream_index)
  
  {
  
      int ret;
  
      int got_frame;
  
  
  
      if (!(ofmt_ctx->streams[stream_index]->codec->codec->capabilities &amp;
  
                  AV_CODEC_CAP_DELAY))
  
          return 0;
  
  
  
      while (1) {
  
          av_log(NULL, AV_LOG_INFO, "Flushing stream #%u encoder\n", stream_index);
  
          ret = encode_write_frame(NULL, stream_index, &amp;got_frame);
  
          if (ret &lt; 0)
  
              break;
  
          if (!got_frame)
  
              return 0;
  
      }
  
      return ret;
  
  }
  
  
  
  int main(int argc, char **argv)
  
  {
  
      int ret;
  
      AVPacket packet = { .data = NULL, .size = 0 };
  
      AVFrame *frame = NULL;
  
      enum AVMediaType type;
  
      unsigned int stream_index;
  
      unsigned int i;
  
      int got_frame;
  
      int (*dec_func)(AVCodecContext *, AVFrame *, int *, const AVPacket *);
  
  
  
      if (argc != 3) {
  
          av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file="file" /> <output file="file">\n", argv[0]);
  
          return 1;
  
      }
  
  
  
      av_register_all();
  
      avfilter_register_all();
  
      avformat_network_init();
  
  
  
      if ((ret = open_input_file(argv[1])) &lt; 0)
  
          goto end;
  
      if ((ret = open_output_file(argv[2])) &lt; 0)
  
          goto end;
  
      if ((ret = init_filters()) &lt; 0)
  
          goto end;
  
  
  
      /* read all packets */
  
      while (1) {
  
          if ((ret = av_read_frame(ifmt_ctx, &amp;packet)) &lt; 0)
  
              break;
  
          stream_index = packet.stream_index;
  
          type = ifmt_ctx->streams[packet.stream_index]->codec->codec_type;
  
          av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n",
  
                  stream_index);
  
  
  
          if (filter_ctx[stream_index].filter_graph) {
  
              av_log(NULL, AV_LOG_DEBUG, "Going to reencode&amp;filter the frame\n");
  
              frame = av_frame_alloc();
  
              if (!frame) {
  
                  ret = AVERROR(ENOMEM);
  
                  break;
  
              }
  
              av_packet_rescale_ts(&amp;packet,
  
                                   ifmt_ctx->streams[stream_index]->time_base,
  
                                   ifmt_ctx->streams[stream_index]->codec->time_base);
  
              dec_func = (type == AVMEDIA_TYPE_VIDEO) ? avcodec_decode_video2 :
  
                  avcodec_decode_audio4;
  
              ret = dec_func(ifmt_ctx->streams[stream_index]->codec, frame,
  
                      &amp;got_frame, &amp;packet);
  
              if (ret &lt; 0) {
  
                  av_frame_free(&amp;frame);
  
                  av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");
  
                  break;
  
              }
  
  
  
              if (got_frame) {
  
                  frame->pts = av_frame_get_best_effort_timestamp(frame);
  
                  ret = filter_encode_write_frame(frame, stream_index);
  
                  av_frame_free(&amp;frame);
  
                  if (ret &lt; 0)
  
                      goto end;
  
              } else {
  
                  av_frame_free(&amp;frame);
  
              }
  
          } else {
  
              /* remux this frame without reencoding */
  
              av_packet_rescale_ts(&amp;packet,
  
                                   ifmt_ctx->streams[stream_index]->time_base,
  
                                   ofmt_ctx->streams[stream_index]->time_base);
  
  
  
              ret = av_interleaved_write_frame(ofmt_ctx, &amp;packet);
  
              if (ret &lt; 0)
  
                  goto end;
  
          }
  
          av_packet_unref(&amp;packet);
  
      }
  
  
  
      /* flush filters and encoders */
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          /* flush filter */
  
          if (!filter_ctx[i].filter_graph)
  
              continue;
  
          ret = filter_encode_write_frame(NULL, i);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Flushing filter failed\n");
  
              goto end;
  
          }
  
  
  
          /* flush encoder */
  
          ret = flush_encoder(i);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Flushing encoder failed\n");
  
              goto end;
  
          }
  
      }
  
  
  
      av_write_trailer(ofmt_ctx);
  
  end:
  
      av_packet_unref(&amp;packet);
  
      av_frame_free(&amp;frame);
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          avcodec_close(ifmt_ctx->streams[i]->codec);
  
          if (ofmt_ctx &amp;&amp; ofmt_ctx->nb_streams > i &amp;&amp; ofmt_ctx->streams[i] &amp;&amp; ofmt_ctx->streams[i]->codec)
  
              avcodec_close(ofmt_ctx->streams[i]->codec);
  
          if (filter_ctx &amp;&amp; filter_ctx[i].filter_graph)
  
              avfilter_graph_free(&amp;filter_ctx[i].filter_graph);
  
      }
  
      av_free(filter_ctx);
  
      avformat_close_input(&amp;ifmt_ctx);
  
      if (ofmt_ctx &amp;&amp; !(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE))
  
          avio_closep(&amp;ofmt_ctx->pb);
  
      avformat_free_context(ofmt_ctx);
  
  
  
      if (ret &lt; 0)
  
          av_log(NULL, AV_LOG_ERROR, "Error occurred: %s\n", av_err2str(ret));
  
  
  
      return ret ? 1 : 0;
  
  }
  
  </output>

  When we run this we are getting this error :

  Input #0, rtsp, from 'rtsp://localhost:8554/live':
  
    Metadata:
  
      title           : Unnamed
  
      comment         : N/A
  
    Duration: N/A, start: 5294.642467, bitrate: N/A
  
      Stream #0:0: Video: h264 (Constrained Baseline), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 30 fps, 30 tbr, 90k tbn, 60 tbc
  
  [libx264 @ 0xe87c80] Specified pixel format -1 is invalid or not supported
  
  Cannot open video encoder for stream #0
  
  codec : 28 and pix :12
  
  Error occurred: Invalid argument

  But I could see that the correct pixel format macro "AV_PIX_FMT_YUV420P" is provided.

  UPDATE 1 :
  This is the section in ffmpeg where the error is thrown from(utils.c line 1547) :

   if (avctx->codec->pix_fmts) {
  
              for (i = 0; avctx->codec->pix_fmts[i] != AV_PIX_FMT_NONE; i++)
  
                  if (avctx->pix_fmt == avctx->codec->pix_fmts[i])
  
                      break;
  
              if (avctx->codec->pix_fmts[i] == AV_PIX_FMT_NONE
  
                  && !((avctx->codec_id == AV_CODEC_ID_MJPEG || avctx->codec_id == AV_CODEC_ID_LJPEG)
  
                       && avctx->strict_std_compliance <= FF_COMPLIANCE_UNOFFICIAL)) {
  
                  char buf[128];
  
                  snprintf(buf, sizeof(buf), "%d", avctx->pix_fmt);
  
                  av_log(avctx, AV_LOG_ERROR, "Specified pixel format %s is invalid or not supported\n",
  
                         (char *)av_x_if_null(av_get_pix_fmt_name(avctx->pix_fmt), buf));
  
                  ret = AVERROR(EINVAL);
  
                  goto free_and_end;
  
              }

  Can someone suggest a solution for this.

  Thanks

• How to get audio track assignment in ffmpeg

  16 février 2012, par David542

  Is there a way to get the audio track assignment in ffmpeg ? For example, if you are in QuickTime, you can view info (Command - I), and see the track assignment. It looks something like this :

  Apple ProRes 422 (HQ), 1,920 x 1,080
  
  Linear PCM, 24 bit little-endian signed integer, 48000 Hz, **Left**
  
  Linear PCM, 24 bit little-endian signed integer, 48000 Hz, **Right**
  
  Linear PCM, 24 bit little-endian signed integer, 48000 Hz, **Center**
  
  Linear PCM, 24 bit little-endian signed integer, 48000 Hz, **LFE Screen**
  
  etc...

  When I do $ ffmpeg -i, it does not show the track assignments —

  Stream #0:12(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels, s32, 1152 kb/s
  
  Metadata:
  
    creation_time   : 2010-09-16 02:23:49
  
    handler_name    : ?Apple Alias Data Handler
  
  Stream #0:13(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels, s32, 1152 kb/s
  
  Metadata:
  
    creation_time   : 2010-09-16 02:23:49
  
    handler_name    : ?Apple Alias Data Handler
  
  Stream #0:14(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, 1 channels, s32, 1152 kb/s
  
  Metadata:
  
    creation_time   : 2010-09-16 02:23:49
  
    handler_name    : ?Apple Alias Data Handler
  
  Stream #0:15(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, stereo, s32, 2304 kb/s
  
  Metadata:
  
    creation_time   : 2010-09-16 02:23:49
  
    handler_name    : ?Apple Alias Data Handler
  
  Stream #0:16(eng): Audio: pcm_s24le (in24 / 0x34326E69), 48000 Hz, stereo, s32, 2304 kb/s

  Is there a way to get the track assignments in ffmpeg or another program ?