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• How to silent the MP3 decoding process

  3 août 2019, par Golu

  I am learning ffmpeg and I made a MP3 decoder but when I am executing it , some kind of information is printing on my terminal but I don’t want it. So how to silent it ?

  Here is code (full code)

  /* FFmpeg Usage Example
  
   * Date : 28 July 2019
  
   */
  
  #include 
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavutil></libavutil>avutil.h>
  
  #include 
  
  
  
  int decode_packet(AVCodecContext*, AVPacket*, AVFrame*);
  
  
  
  int main(void) {
  
          AVFormatContext *pFormatContext = avformat_alloc_context();
  
          AVCodecParameters *pCodecParameters = NULL;
  
          if(avformat_open_input(&amp;pFormatContext,"song.mp3",NULL,NULL)!=0) {
  
                  fprintf(stderr,"Could not open file\n");
  
                  return -1;
  
          }
  
          if(avformat_find_stream_info(pFormatContext,NULL)&lt;0) {
  
                  fprintf(stderr,"Could not find stream\n");
  
                  return -1;
  
          }
  
  
  
          size_t stream_index = 0;
  
          for(;stream_indexnb_streams;stream_index++) {
  
                  if(pFormatContext->streams[stream_index]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
  
                          pCodecParameters = pFormatContext->streams[stream_index]->codecpar;
  
                  }
  
                          break;
  
          }
  
  
  
          if(stream_index == -1) {
  
                  fprintf(stderr,"could not retrive stream info from file\n");
  
                  return -1;
  
          }
  
          AVStream *stream = pFormatContext->streams[stream_index];
  
          pCodecParameters = stream->codecpar;
  
          AVCodec *cdc = avcodec_find_decoder(pCodecParameters->codec_id);
  
          AVCodecContext *cdc_ctx = avcodec_alloc_context3(cdc);
  
          assert(pCodecParameters);
  
  
  
          if(avcodec_parameters_to_context(cdc_ctx,pCodecParameters) &lt; 0) {
  
                  fprintf(stderr,"Can't copy params to codec context\n");
  
                  return -1;
  
          }
  
  
  
          if(avcodec_open2(cdc_ctx,cdc,NULL) &lt; 0) {
  
                  fprintf(stderr,"Failed to open decoder for stream\n");
  
                  return -1;
  
          }
  
  
  
          AVFrame *frame = av_frame_alloc();
  
          if(!frame) {
  
                  fprintf(stderr,"could not allocate memory for frame\n");
  
                  return -1;
  
          }
  
  
  
          AVPacket *packet = av_packet_alloc();
  
  //      av_init_packet(&amp;packet);
  
          if(!packet) {
  
                  fprintf(stderr,"could not allocate memory for packet");
  
                  return -1;
  
          }
  
  
  
          packet->data=NULL;
  
          packet->size=0;
  
          // lets read the packets
  
          while(av_read_frame(pFormatContext,packet) >= 0) {
  
                  if(packet->stream_index==stream_index) {
  
                          int response = 0 ;
  
              response = decode_packet(cdc_ctx,packet,frame);
  
  
  
                          if(response &lt; 0)
  
                                  continue;
  
                  }
  
          av_packet_unref(packet);
  
          }
  
  
  
          return 0;
  
  }
  
  
  
  int decode_packet(AVCodecContext *cdc_ctx , AVPacket *pkt, AVFrame *frm) {
  
      int response = avcodec_send_packet(cdc_ctx,pkt);
  
      if(response &lt; 0)
  
          return response;
  
      while(response >= 0) {
  
          response = avcodec_receive_frame(cdc_ctx,frm);
  
          if(response == AVERROR(EAGAIN) || response == AVERROR_EOF)
  
              return -1;
  
          else if(response &lt; 0)
  
              return response;
  
      }
  
      return 0;
  
  }

  Expected behaviour : nothing should be printed on screen

  Actual behaviour : some kind of logs are printing automatically

  Here is output logs ( some of them )

  [mp3float @ 0x75172e7400] overread, skip -6 enddists: -5 -5         
  
  [mp3float @ 0x75172e7400] overread, skip -7 enddists: -6 -6
  
  [mp3float @ 0x75172e7400] overread, skip -6 enddists: -5 -5
  
  [mp3float @ 0x75172e7400] overread, skip -6 enddists: -4 -4

• split quadri audio file into 4 monos

  23 août 2019, par user2216280

  I have a quadri audio file (one stream of 4tracks) and I would like to make 4 monos track from that stream/

  ffmpeg -i TRACK-026.wav -filter_complex "channelsplit=channel_layout=4[Perche][MixHf][hf1][hf2]" -map "[Perche]" perche.wav -map "[MixHF]" MixHF.wav -map "[hf1]" hf1.wav -map "[hf2]" hf2.wav

  here’s the full log :

  Guessed Channel Layout for Input Stream #0.0 : 4.0
  
  Input #0, wav, from 'TRACK-026.wav':
  
    Metadata:
  
  comment         : sSPEED=030.000-ND
  
                  : sTAKE=026
  
                  : sUBITS=$00000000
  
                  : sSWVER=2.10.71
  
                  : sSCENE=Track
  
                  : sFILENAME=TRACK-026.WAV
  
                  : sTAPE=190822
  
                  : sCIRCLED=FALSE
  
                  : sTRK1=Perche
  
                  : sTRK2=MixHF
  
                  : sTRK4=hf1
  
                  : sTRK5=hf2
  
                  : sNOTE=
  
                  :
  
  encoded_by      : SoundDev: MixPre-10T QD031734201
  
  originator_reference: USSDVQD0317342017190822DQR000101
  
  date            : 2019-08-22
  
  creation_time   : 13:26:54
  
  time_reference  : 0
  
  coding_history  : A=PCM,F=48000,W=24,M=multi,R=48000,T=4 Ch
  
                  :
  
  Duration: 00:32:19.35, bitrate: 4608 kb/s
  
  Stream #0:0: Audio: pcm_s24le ([1][0][0][0] / 0x0001), 48000 Hz, 4.0, s32 (24 bit), 4608 kb/s
  
  [AVFilterGraph @ 000002293f28d500] No output pad can be associated to link label 'MixHf'.
  
  Error initializing complex filters.
  
  Invalid argument

• Using Unicast RTSP URIs via ffmpeg

  6 août 2019, par Chris Marshall

  I’m fairly new to ffmpeg, so I’d certainly appreciate being given an "M" to "RTFM." The ffmpeg docs are...not-so-easy...to navigate, but I’m trying.

  The goal is to develop a compiled server that incorporates ffmpeg, but first, I need to get it working via CLI.

  I have a standard AXIS Surveillance camera (AXIS M5525-E), set up as an ONVIF device (but that isn’t really relevant to this issue).

  When I query it, I get the following URI as its video streaming URI :

  rtsp://192.168.4.12/onvif-media/media.amp?profile=profile_1_jpeg&streamtype=unicast

  The IP is local to a sandboxed network.

  I add the authentication parameters to it, like so :

  rtsp://<login>:<password>@192.168.4.12/onvif-media/media.amp?profile=profile_1_jpeg&amp;streamtype=unicast
  
  </password></login>

  (Yeah, I know that’s not secure, but this is just for testing and feasibility study. The whole damn sandbox is an insecure mess).

  Now, if I use VLC to open the URI, it works great (of course). Looking at it with a packet analyzer, I see the following negotiation between the device and my computer (at .2 - Clipped for brevity) :

  Id = 11
  
  Source = 192.168.4.12
  
  Destination = 192.168.4.2
  
  Captured Length = 82
  
  Packet Length = 82
  
  Protocol = TCP
  
  Date Received = 2019-08-06 12:18:37 +0000
  
  Time Delta = 1.342024087905884
  
  Information = 554 -> 53755 ([ECN, ACK, SYN], Seq=696764098, Ack=3139240483, Win=28960)
  
                      °
  
                      °
  
                      °
  
  Id = 48
  
  Source = 192.168.4.12
  
  Destination = 192.168.4.2
  
  Captured Length = 366
  
  Packet Length = 366
  
  Protocol = TCP
  
  Date Received = 2019-08-06 12:18:38 +0000
  
  Time Delta = 2.09382700920105
  
  Information = 554 -> 53755 ([ACK, PUSH], Seq=696765606, Ack=3139242268, Win=1073)

  Followed immediately by UDP stream packets.

  If, however, I feed the same URI to ffmpeg :

  ffmpeg -i rtsp://<login>:<password>@192.168.4.12/onvif-media/media.amp?profile=profile_1_jpeg&amp;streamtype=unicast -c:v libx264 -crf 21 -preset veryfast -g 30 -sc_threshold 0 -f hls -hls_time 4 /Volumes/Development/webroot/fftest/stream.m3u8
  
  </password></login>

  I get nothing. No negotiation at all between the device and my computer.

  After that, if I then remove the &streamtype=unicast argument, I get a negotiation, and a stream :

  Id = 10
  
  Source = 192.168.4.12
  
  Destination = 192.168.4.2
  
  Captured Length = 82
  
  Packet Length = 82
  
  Protocol = TCP
  
  Date Received = 2019-08-06 10:37:48 +0000
  
  Time Delta = 3.047425985336304
  
  Information = 554 -> 49606 ([ECN, ACK, SYN], Seq=457514925, Ack=2138974173, Win=28960)
  
                      °
  
                      °
  
                      °
  
  Id = 31
  
  Source = 192.168.4.12
  
  Destination = 192.168.4.2
  
  Captured Length = 345
  
  Packet Length = 345
  
  Protocol = TCP
  
  Date Received = 2019-08-06 10:37:49 +0000
  
  Time Delta = 3.840152025222778
  
  Information = 554 -> 49606 ([ACK, PUSH], Seq=457516393, Ack=2138975704, Win=1039)

  I will, of course, be continuing to work out why this is [not] happening, and will post any solutions that I find, but, like I said, I’m fairly new to this, so it’s entirely possible that I’m missing some basic stuff, and would appreciate any guidance.

  Thanks !