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• FFMPEG and SDL : No available audio device [closed]

  5 mars 2013, par user948620

  I have a sample audio program. compiled using gcc

  #include avcodec.h>
  #include avformat.h>
  #include SDL.h>
  #include SDL_thread.h>
  
  
  #define FILENAME "/Desktop/sample.mp3"
  
  #define SDL_AUDIO_BUFFER_SIZE 1024
  #define SDL_AUDIO_DRIVER_COREAUDIO 1
  
  typedef struct PacketQueue {
    AVPacketList *first_pkt, *last_pkt;
    int nb_packets;
    int size;
    SDL_mutex *mutex;
    SDL_cond *cond;
  } PacketQueue;
  
  PacketQueue audioq;
  
  void audio_callback(void *userdata, Uint8 *stream, int len) {
  
    AVCodecContext *aCodecCtx = (AVCodecContext *)userdata;
    int len1, audio_size;
  
    static uint8_t audio_buf[(AVCODEC_MAX_AUDIO_FRAME_SIZE * 3) / 2];
    static unsigned int audio_buf_size = 0;
    static unsigned int audio_buf_index = 0;
  
    while(len > 0) {
      if(audio_buf_index >= audio_buf_size) {
        /* We have already sent all our data; get more */
        audio_size = audio_decode_frame(aCodecCtx, audio_buf, sizeof(audio_buf));
        if(audio_size < 0) {
      /* If error, output silence */
      audio_buf_size = 1024; // arbitrary?
      memset(audio_buf, 0, audio_buf_size);
        } else {
      audio_buf_size = audio_size;
        }
        audio_buf_index = 0;
      }
      len1 = audio_buf_size - audio_buf_index;
      if(len1 > len)
        len1 = len;
      memcpy(stream, (uint8_t *)audio_buf + audio_buf_index, len1);
      len -= len1;
      stream += len1;
      audio_buf_index += len1;
    }
  }
  
  
  void packet_queue_init(PacketQueue *q) { // initialize packet que
    memset(q, 0, sizeof(PacketQueue));
    q->mutex = SDL_CreateMutex();
    q->cond = SDL_CreateCond();
  }
  
  int packet_queue_put(PacketQueue *q, AVPacket *pkt) {
  
    AVPacketList *pkt1;
    if(av_dup_packet(pkt) < 0) {
      return -1;
    }
    pkt1 = av_malloc(sizeof(AVPacketList));
    if (!pkt1)
      return -1;
    pkt1->pkt = *pkt;
    pkt1->next = NULL;
  
  
    SDL_LockMutex(q->mutex);
  
    if (!q->last_pkt)
      q->first_pkt = pkt1;
    else
      q->last_pkt->next = pkt1;
    q->last_pkt = pkt1;
    q->nb_packets++;
    q->size += pkt1->pkt.size;
    SDL_CondSignal(q->cond);
  
    SDL_UnlockMutex(q->mutex);
    return 0;
  }
  
  int quit = 0;
  
  static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) { // get packet
    AVPacketList *pkt1;
    int ret;
  
    SDL_LockMutex(q->mutex);
  
    for(;;) {
  
      if(quit) {
        ret = -1;
        break;
      }
  
      pkt1 = q->first_pkt;
      if (pkt1) {
        q->first_pkt = pkt1->next;
        if (!q->first_pkt)
      q->last_pkt = NULL;
        q->nb_packets--;
        q->size -= pkt1->pkt.size;
        *pkt = pkt1->pkt;
        av_free(pkt1);
        ret = 1;
        break;
      } else if (!block) {
        ret = 0;
        break;
      } else {
        SDL_CondWait(q->cond, q->mutex);
      }
    }
    SDL_UnlockMutex(q->mutex);
    return ret;
  }
  
  
  int audio_decode_frame(AVCodecContext *aCodecCtx, uint8_t *audio_buf,
                         int buf_size) { // decode audio
  
    static AVPacket pkt;
    static uint8_t *audio_pkt_data = NULL;
    static int audio_pkt_size = 0;
  
    int len1, data_size;
  
    for(;;) {
      while(audio_pkt_size > 0) {
        data_size = buf_size;
        //len1 = avcodec_decode_audio3(aCodecCtx, (int16_t *)audio_buf, &data_size, audio_pkt_data, audio_pkt_size);
      len1 = avcodec_decode_audio3(aCodecCtx, (int16_t *)audio_buf, &data_size, audio_pkt_data);
        if(len1 < 0) {
      /* if error, skip frame */
      audio_pkt_size = 0;
      break;
        }
        audio_pkt_data += len1;
        audio_pkt_size -= len1;
        if(data_size <= 0) {
      /* No data yet, get more frames */
      continue;
        }
        /* We have data, return it and come back for more later */
        return data_size;
      }
      if(pkt.data)
        av_free_packet(&pkt);
  
      if(quit) {
        return -1;
      }
  
      if(packet_queue_get(&audioq, &pkt, 1) < 0) {
        return -1;
      }
      audio_pkt_data = pkt.data;
      audio_pkt_size = pkt.size;
    }
  }
  
  
  int main()  // main
  {
  
  
  // starts here
  
  AVFormatContext *pFormatCtx;
  AVCodecContext *pCodecCtx;
  AVCodec *pCodec;
  
  SDL_AudioSpec   wanted_spec, spec;
  
  int res;
  int audioStream;
  
  av_register_all();
  avdevice_register_all();
  res = av_open_input_file(&pFormatCtx,FILENAME,NULL,0,NULL); // input mp3 file
  printf("%i\n",res);
  
  res = av_find_stream_info(pFormatCtx); // find stream info
  printf("%i\n",res);
  
  
  //dump_format(pFormatCtx,0,FILENAME,0);
  
  int i;
  for(i=0;inb_streams;i++) { // get codec index
      if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
          audioStream = i;
      }
  }
  
  if(audioStream == -1) {
      printf("WALANG CODEC %i",audioStream);
      return audioStream;
  } else {
      printf("May Codec %i\n",audioStream);
  }
  
  pCodecCtx = pFormatCtx->streams[audioStream]->codec;
  
  /*
  pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
  if(pCodec == NULL) {
      fprintf(stderr, "Unsupported codec!\n");
      return -1;
  }
  
  if(avcodec_open(pCodecCtx,pCodec) < 0) {
      fprintf(stderr, "Ayaw buksan ang codec!\n");
      return -1;
  }
  */
  
  wanted_spec.freq = pCodecCtx->sample_rate;
  wanted_spec.format = AUDIO_S16SYS;
  wanted_spec.channels = pCodecCtx->channels;
  wanted_spec.silence = 0;
  wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
  wanted_spec.callback = audio_callback;
  wanted_spec.userdata = pCodecCtx;
  
  if(SDL_OpenAudio(&wanted_spec, &spec) < 0) {
    fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
    return -1;
  }
  
  
  pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
  
  if(!pCodec) {
  fprintf(stderr, "Walang Codec, Unsupported");
  return -1;
  }
  
  avcodec_open(pCodecCtx,pCodec);
  
  packet_queue_init(&audioq);
  SDL_PauseAudio(0);
  
  
  
  
  return 0;
  }
  

  It compiles successfully. but when i run the program it says

  SDL_OpenAudio: No available audio device

  I am using SDL Dev library and FFMpeg on Ubuntu 11.10

  How to solve this problem?

• AR Drone 2 and ffserver + ffmpeg streaming

  5 mars 2013, par BjarkeHS

  I want to be able to restream the video feed of the AR Drone 2 from a Debian Server to Flash.

  I am aware that the AR Drone uses the codec p264. I'm totally green when it comes to video codecs, so I don't know what will be suitable for the goal I want to achieve?

  I have been able to stream the video feed from the AR Drone but with very high latency and extremely low quality, compared to when I directly connect to the AR Drone using ffplay.

  I currently use the .swf example in the standard ffserver.conf:

  
  Feed feed1.ffm
  Format swf
  VideoFrameRate 30
  VideoIntraOnly
  NoAudio
  
  

  And the settings for the .ffm Feed are as follows:

  
  File /tmp/feed1.ffm
  FileMaxSize 17K
  ACL allow 127.0.0.1
  NoAudio
  
  

  The command I use for giving input to the ffserver feed:

  ffmpeg -i http://192.168.1.1:5555 http://localhost:8090/feed1.ffm
  

  How am I able to achieve lower latency and higher quality, since the stream is currently unwatchable?

• Use ffmpeg to create the wmv progressive download

  5 mars 2013, par Amol

  I want to create the WMV files for Progressive download and internet streaming using the ffmpeg. How can I use the ffmpeg commands for this?

  Any help will be appreciated...

• Crash on ffmpeg avcodec_encode_video in a Console app

  5 mars 2013, par Robel sharma

  I want make an encoder which encode a raw image into h263 format.But after loading and initializing ffmpeg library I got crash on avcodec_encode_video for a demo image.

  int _tmain(int argc, _TCHAR* argv[]) {
      avcodec_register_all();
      AVCodec *codec;
      AVCodecContext *c= NULL;
      int i, ret, x, y, got_output;
      FILE *f;
      AVFrame *frame;
      AVPacket pkt;
  
      int out_size, size, outbuf_size;
  
      AVFrame *picture;
      uint8_t *outbuf, *picture_buf;
  
      AVRational rp;   
  
      rp.den = 1;
      rp.num = 25;
      uint8_t endcode[] = { 0, 0, 1, 0xb7 };
  
      codec = avcodec_find_encoder(CODEC_ID_H263);
  
      c = avcodec_alloc_context3(codec);
      picture= avcodec_alloc_frame();
      c->bit_rate = 400000;
      /* resolution must be a multiple of two */
      c->width = 352;
      c->height = 288;
      /* frames per second */
      //c->time_base= (AVRational){1,25};
      c->time_base = rp;
      c->gop_size = 10; /* emit one intra frame every ten frames */
      c->max_b_frames=1;
      c->pix_fmt = PIX_FMT_YUV420P;
      avcodec_open(c, codec);
  
  
      outbuf_size = 100000;
      outbuf = (uint8_t*)malloc(outbuf_size);
      size = c->width * c->height;
      picture_buf = (uint8_t*)malloc((size * 3) / 2); /* size for YUV 420 */
  
      picture->data[0] = picture_buf;
      picture->data[1] = picture->data[0] + size;
      picture->data[2] = picture->data[1] + size / 4;
      picture->linesize[0] = c->width;
      picture->linesize[1] = c->width / 2;
      picture->linesize[2] = c->width / 2;
  
      /* encode 1 second of video */
      for(i=0;i<25;i++) {
          fflush(stdout);
          /* prepare a dummy image */
          /* Y */
          for(y=0;yheight;y++) {
              for(x=0;xwidth;x++) {
                  picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3;
              }
          }
          /* Cb and Cr */
          for(y=0;yheight/2;y++) {
              for(x=0;xwidth/2;x++) {
                  picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2;
                  picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5;
              }
          }
          /* encode the image */
  
          **Crash is here** --->                 ///////////////////////////////////////////////////
          out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
  
          printf("encoding frame %3d (size=%5d)\n", i, out_size);
          fwrite(outbuf, 1, out_size, f);
      }
      /* get the delayed frames */
      for(; out_size; i++) {
          fflush(stdout);
          out_size = avcodec_encode_video(c, outbuf, outbuf_size, NULL);
          printf("write frame %3d (size=%5d)\n", i, out_size);
          fwrite(outbuf, 1, out_size, f);
      }
      /* add sequence end code to have a real mpeg file */
      outbuf[0] = 0x00;
      outbuf[1] = 0x00;
      outbuf[2] = 0x01;
      outbuf[3] = 0xb7;
      fwrite(outbuf, 1, 4, f);
      fclose(f);
      free(picture_buf);
      free(outbuf);
  
      avcodec_close(c);
      av_free(c);
      av_free(picture);
      printf("\n");
      return 0;
  }
  

• To change the audio of the running live video

  5 mars 2013, par Tushar Sharma

  I want to change the audio of the running video in my application. For example, when I open my application it contain camera screen. Now I want that I can see the video that I am watching from the camera but the audio get changed.