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• Encoiding Video Frame Error with VAAPI encoding [on hold]

  26 octobre 2018, par Tcor5

  I’m attempting to convert one of the FFMPEG Muxing examples (https://ffmpeg.org/doxygen/2.8/muxing_8c.html) to use VAAPI hardware encoding, using https://www.ffmpeg.org/doxygen/trunk/vaapi_transcode_8c-example.html as an example.

  The problem is when I call avcodec_open2, it returns :
  Error encoding video frame : Input/output error

  I believe I have set up all the HW contexts and frames appropriately but it seems the encoding is failing due to an invalid VASurface ID.
  Does anyone have any tips on how to resolve/troubleshoot this ?

  Thanks

  This is the entire shell printout :

  [AVHWDeviceContext @ 0x55acd607dd40] Opened VA display via X11 display :0.
  
  [AVHWDeviceContext @ 0x55acd607dd40] libva: VA-API version 1.1.0
  
  [AVHWDeviceContext @ 0x55acd607dd40] libva: va_getDriverName() returns 0
  
  [AVHWDeviceContext @ 0x55acd607dd40] libva: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
  
  [AVHWDeviceContext @ 0x55acd607dd40] libva: Found init function __vaDriverInit_1_1
  
  [AVHWDeviceContext @ 0x55acd607dd40] libva: va_openDriver() returns 0
  
  [AVHWDeviceContext @ 0x55acd607dd40] Initialised VAAPI connection: version 1.1
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x32315659 -> yuv420p.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x30323449 -> yuv420p.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x3231564e -> nv12.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x32595559 -> yuyv422.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x59565955 -> uyvy422.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x48323234 -> yuv422p.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x58424752 -> rgb0.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x58524742 -> bgr0.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Format 0x30313050 -> p010le.
  
  [AVHWDeviceContext @ 0x55acd607dd40] Matched "Intel i965 driver for Intel(R) Skylake - 2.1.0" as known driver "Intel i965 (Quick Sync)".
  
  [AVHWDeviceContext @ 0x55acd609dc40] Opened VA display via X11 display :0.
  
  [AVHWDeviceContext @ 0x55acd609dc40] libva: VA-API version 1.1.0
  
  [AVHWDeviceContext @ 0x55acd609dc40] libva: va_getDriverName() returns 0
  
  [AVHWDeviceContext @ 0x55acd609dc40] libva: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
  
  [AVHWDeviceContext @ 0x55acd609dc40] libva: Found init function __vaDriverInit_1_1
  
  [AVHWDeviceContext @ 0x55acd609dc40] libva: va_openDriver() returns 0
  
  [AVHWDeviceContext @ 0x55acd609dc40] Initialised VAAPI connection: version 1.1
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x32315659 -> yuv420p.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x30323449 -> yuv420p.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x3231564e -> nv12.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x32595559 -> yuyv422.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x59565955 -> uyvy422.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x48323234 -> yuv422p.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x58424752 -> rgb0.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x58524742 -> bgr0.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Format 0x30313050 -> p010le.
  
  [AVHWDeviceContext @ 0x55acd609dc40] Matched "Intel i965 driver for Intel(R) Skylake - 2.1.0" as known driver "Intel i965 (Quick Sync)".
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000000.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Direct mapping possible.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000001.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000002.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000003.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000004.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000005.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000006.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000007.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000008.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000009.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x400000a.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x400000b.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x400000c.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x400000d.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x400000e.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x400000f.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000010.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000011.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000012.
  
  [AVHWFramesContext @ 0x55acd60bbb00] Created surface 0x4000013.
  
  [h264_vaapi @ 0x55acd60ba3c0] Using nv12 as format of reconstructed frames.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x4000014.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Direct mapping possible.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x4000015.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x4000016.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x4000017.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x4000018.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x4000019.
  
  [AVHWFramesContext @ 0x55acd60bcec0] Created surface 0x400001a.
  
  [h264_vaapi @ 0x55acd60ba3c0] Using variable-bitrate = 400000 bps.
  
  [h264_vaapi @ 0x55acd60ba3c0] Encode frame: 352x288 (0).
  
  [h264_vaapi @ 0x55acd60ba3c0] Pictures: IDR (0/0)
  
  [h264_vaapi @ 0x55acd60ba3c0] Issuing encode for pic 0/0 as type IDR.
  
  [h264_vaapi @ 0x55acd60ba3c0] No reference pictures.
  
  [h264_vaapi @ 0x55acd60ba3c0] Input surface is 0.
  
  [h264_vaapi @ 0x55acd60ba3c0] Recon surface is 0x400001a.
  
  [h264_vaapi @ 0x55acd60ba3c0] Allocated output buffer 0x8000000
  
  [h264_vaapi @ 0x55acd60ba3c0] Output buffer is 0x8000000.
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (27) is 0x8000001.
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (27) is 0x8000002.
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (27) is 0x8000003.
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (27) is 0x8000004.
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (22) is 0x8000005.
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (23) is 0x8000006.
  
  [h264_vaapi @ 0x55acd60ba3c0] Packed header buffer (1) is 0x8000007/0x8000008 (376 bits).
  
  [h264_vaapi @ 0x55acd60ba3c0] Packed header buffer (4) is 0x8000009/0x800000a (944 bits).
  
  [h264_vaapi @ 0x55acd60ba3c0] Packed header buffer (3) is 0x800000b/0x800000c (72 bits).
  
  [h264_vaapi @ 0x55acd60ba3c0] Param buffer (24) is 0x800000d.
  
  [h264_vaapi @ 0x55acd60ba3c0] Failed to begin picture encode issue: 6 (invalid VASurfaceID).
  
  [h264_vaapi @ 0x55acd60ba3c0] Encode failed: -5.
  
  Error encoding video frame: Input/output error

  This is the code that i’m using :

  #include 
  
  #include 
  
  #include 
  
  #include 
  
  
  
  #include <libavutil></libavutil>avassert.h>
  
  #include <libavutil></libavutil>channel_layout.h>
  
  #include <libavutil></libavutil>opt.h>
  
  #include <libavutil></libavutil>mathematics.h>
  
  #include <libavutil></libavutil>timestamp.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libswscale></libswscale>swscale.h>
  
  #include <libswresample></libswresample>swresample.h>
  
  
  
  //HW Encoding
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavutil></libavutil>pixdesc.h>
  
  #include <libavutil></libavutil>hwcontext.h>
  
  
  
  #define STREAM_DURATION   10.0
  
  #define STREAM_FRAME_RATE 25 /* 25 images/s */
  
  /* default pix_fmt */
  
  #define STREAM_PIX_FMT    AV_PIX_FMT_VAAPI
  
  #define SCALE_FLAGS SWS_BICUBIC
  
  
  
  #define LINUX_LIVE_STREAM   // enables linux live stream
  
  #define MAX_NAME_LEN 256
  
  static AVBufferRef *hw_device_ctx = NULL; //HW Encoding
  
  // a wrapper around a single output AVStream
  
  typedef struct OutputStream {
  
      AVStream *st;
  
      AVCodecContext *enc;
  
      /* pts of the next frame that will be generated */
  
      int64_t next_pts;
  
      int samples_count;
  
      AVFrame *frame;
  
      AVFrame *tmp_frame;
  
      float t, tincr, tincr2;
  
      struct SwsContext *sws_ctx;
  
      struct SwrContext *swr_ctx;
  
  } OutputStream;
  
  
  
  
  
  static int set_hwframe_ctx(AVCodecContext *c, AVBufferRef *hw_device_ctx)
  
  {
  
      AVBufferRef *hw_frames_ref;
  
      AVHWFramesContext *frames_ctx = NULL;
  
      int err = 0;
  
      if (!(hw_frames_ref = av_hwframe_ctx_alloc(hw_device_ctx))) {
  
          fprintf(stderr, "Failed to create VAAPI frame context.\n");
  
          return -1;
  
      }
  
      frames_ctx = (AVHWFramesContext *)(hw_frames_ref->data);
  
      frames_ctx->format    = AV_PIX_FMT_VAAPI;
  
      frames_ctx->sw_format = AV_PIX_FMT_NV12;
  
      frames_ctx->width     = 352;
  
      frames_ctx->height    = 288;
  
      frames_ctx->initial_pool_size = 20;
  
      if ((err = av_hwframe_ctx_init(hw_frames_ref)) &lt; 0) {
  
          fprintf(stderr, "Failed to initialize VAAPI frame context."
  
                  "Error code: %s\n",av_err2str(err));
  
          av_buffer_unref(&amp;hw_frames_ref);
  
          return err;
  
      }
  
      c->hw_frames_ctx = av_buffer_ref(hw_frames_ref);
  
      if (!c->hw_frames_ctx)
  
          err = AVERROR(ENOMEM);
  
      return err;
  
  }
  
  
  
  /* Add an output stream. */
  
  static void add_stream(OutputStream *ost, AVFormatContext *oc,
  
                         AVCodec **codec,
  
                         enum AVCodecID codec_id)
  
  {
  
      AVCodecContext *c;
  
      int i;
  
      int ret; //HW Encoding
  
      const char *enc_name = "h264_vaapi";//HW encoding  
  
      //HW Encoding
  
      ret = av_hwdevice_ctx_create(&amp;hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, NULL, NULL, 0);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Failed to create a VAAPI device. Error code: %s\n", av_err2str(ret));
  
          return -1;
  
      }   
  
      *codec = avcodec_find_encoder_by_name(enc_name);//HW encoding codec
  
      if (!(*codec)) {
  
          fprintf(stderr, "Could not find encoder.\n");
  
          exit(1);
  
      }
  
      ost->st = avformat_new_stream(oc, NULL);
  
      if (!ost->st) {
  
          fprintf(stderr, "Could not allocate stream\n");
  
          exit(1);
  
      }
  
      ost->st->id = oc->nb_streams-1;
  
      c = avcodec_alloc_context3(*codec);
  
      if (!c) {
  
          fprintf(stderr, "Could not alloc an encoding context\n");
  
          exit(1);
  
      }
  
      ost->enc = c;
  
      switch ((*codec)->type) {
  
  
  
      case AVMEDIA_TYPE_VIDEO:
  
          c->codec_id = codec_id;
  
          c->bit_rate = 400000;
  
          /* Resolution must be a multiple of two. */
  
          c->width    = 352;
  
          c->height   = 288;
  
          ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE };
  
          c->time_base       = ost->st->time_base;
  
          c->gop_size      = 12; 
  
          c->pix_fmt       = STREAM_PIX_FMT; 
  
          if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
  
              c->max_b_frames = 2;
  
          }
  
          if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
  
              c->mb_decision = 2;
  
          }
  
      break;
  
      default:
  
          break;
  
      }
  
      if ((ret = set_hwframe_ctx(c, hw_device_ctx)) &lt; 0) {
  
          fprintf(stderr, "Failed to set hwframe context.\n");
  
          exit(1);
  
      }
  
      if (oc->oformat->flags &amp; AVFMT_GLOBALHEADER)
  
          c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  }
  
  /* video output */
  
  static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
  
  {
  
      AVFrame *picture;
  
      int ret;
  
      picture = av_frame_alloc();
  
      if (!picture)
  
          return NULL;
  
      picture->format = AV_PIX_FMT_YUV420P;
  
      picture->width  = width;
  
      picture->height = height;
  
      printf ("pix_fmt = %d \n", pix_fmt);
  
      printf ("picture ->format (pix_fmt) = %d \n", picture->format);
  
      /* allocate the buffers for the frame data */
  
      ret = av_frame_get_buffer(picture, 32);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Could not allocate frame data.\n");
  
          printf ("error : %d \n", ret);
  
          exit(1);
  
      }
  
      return picture;
  
  }
  
  
  
  static void open_video(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
  
  {
  
      int ret;
  
      AVCodecContext *c = ost->enc;
  
      AVDictionary *opt = NULL;
  
      av_dict_copy(&amp;opt, opt_arg, 0);
  
      /* open the codec */
  
      ret = avcodec_open2(c, codec, &amp;opt);
  
      av_dict_free(&amp;opt);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Could not open video codec: %s\n", av_err2str(ret));
  
          exit(1);
  
      }
  
      /* allocate and init a re-usable frame */
  
      printf ("line #%d\n", __LINE__);
  
      ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
  
      if (!ost->frame) {
  
          fprintf(stderr, "Could not allocate video frame\n");
  
          exit(1);
  
      }
  
      printf ("line #%d\n", __LINE__);
  
      /* If the output format is not YUV420P, then a temporary YUV420P
  
       * picture is needed too. It is then converted to the required
  
       * output format. */
  
      ost->tmp_frame = NULL;
  
      if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
  
          ost->tmp_frame = alloc_picture(AV_PIX_FMT_YUV420P, c->width, c->height);
  
          if (!ost->tmp_frame) {
  
              fprintf(stderr, "Could not allocate temporary picture\n");
  
              exit(1);
  
          }
  
      }
  
      /* copy the stream parameters to the muxer */
  
      ret = avcodec_parameters_from_context(ost->st->codecpar, c);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Could not copy the stream parameters\n");
  
          exit(1);
  
      }
  
  }
  
  /* Prepare a dummy image. */
  
  static void fill_yuv_image(AVFrame *pict, int frame_index,
  
                             int width, int height)
  
  {
  
      int x, y, i;
  
      i = frame_index;  
  
      /* Y */
  
      for (y = 0; y &lt; height; y++)
  
          for (x = 0; x &lt; width; x++)
  
              pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3;
  
      /* Cb and Cr */
  
      for (y = 0; y &lt; height / 2; y++) {
  
          for (x = 0; x &lt; width / 2; x++) {
  
              pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2;
  
          }
  
      }
  
  }
  
  
  
  static AVFrame *get_video_frame(OutputStream *ost)
  
  {
  
      AVCodecContext *c = ost->enc;
  
      if (av_compare_ts(ost->next_pts, c->time_base,
  
                        STREAM_DURATION, (AVRational){ 1, 1 }) >= 0)
  
          return NULL;
  
      if (av_frame_make_writable(ost->frame) &lt; 0)
  
          exit(1);
  
      if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
  
          /* as we only generate a YUV420P picture, we must convert it
  
           * to the codec pixel format if needed */
  
          if (!ost->sws_ctx) {
  
              ost->sws_ctx = sws_getContext(c->width, c->height,
  
                                            AV_PIX_FMT_YUV420P,
  
                                            c->width, c->height,
  
                                            AV_PIX_FMT_NV12,
  
                                            SCALE_FLAGS, NULL, NULL, NULL);
  
              if (!ost->sws_ctx) {
  
                  fprintf(stderr,
  
                          "Could not initialize the conversion context\n");
  
                  exit(1);
  
              }
  
          }
  
          printf ("line #%d\n", __LINE__);
  
          fill_yuv_image(ost->tmp_frame, ost->next_pts, c->width, c->height);
  
          printf ("line #%d\n", __LINE__);
  
          sws_scale(ost->sws_ctx, (const uint8_t * const *) ost->tmp_frame->data,
  
                    ost->tmp_frame->linesize, 0, c->height, ost->frame->data,
  
                    ost->frame->linesize);
  
          printf ("line #%d\n", __LINE__);
  
      } else {
  
          fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
  
      }
  
      printf ("line #%d\n", __LINE__);
  
      ost->frame->pts = ost->next_pts++;
  
      return ost->frame;
  
  }
  
  /*
  
   * encode one video frame and send it to the muxer
  
   * return 1 when encoding is finished, 0 otherwise
  
   */
  
  static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
  
  {
  
      int ret;
  
      AVCodecContext *c;
  
      AVFrame *frame;
  
      int got_packet = 0;
  
      AVPacket pkt = { 0 };
  
      AVStream *st;
  
      printf ("line #%d\n", __LINE__);
  
      c = ost->enc;
  
      printf ("line #%d\n", __LINE__);
  
      frame = get_video_frame(ost);
  
      printf ("line #%d\n", __LINE__);
  
      av_init_packet(&amp;pkt);
  
      /* encode the image */
  
      ret = avcodec_encode_video2(c, &amp;pkt, frame, &amp;got_packet);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Error encoding video frame: %s\n", av_err2str(ret));
  
          exit(1);
  
      }
  
      if (got_packet) {
  
          av_packet_rescale_ts(&amp;pkt, c->time_base, ost->st->time_base);
  
          pkt.stream_index = ost->st->index;
  
          ret = av_interleaved_write_frame(oc, &amp;pkt);
  
          } else {
  
               ret = 0;
  
          }
  
       if (ret &lt; 0) {
  
           fprintf(stderr, "Error while writing video frame: %s\n", av_err2str(ret));
  
           exit(1);
  
       }
  
      return (frame || got_packet) ? 0 : 1;  
  
  }
  
  
  
  static void close_stream(AVFormatContext *oc, OutputStream *ost)
  
  {
  
      avcodec_free_context(&amp;ost->enc);
  
      av_frame_free(&amp;ost->frame);
  
      av_frame_free(&amp;ost->tmp_frame);
  
      sws_freeContext(ost->sws_ctx);
  
      swr_free(&amp;ost->swr_ctx);
  
  }
  
  
  
  /**************************************************************/
  
  /* media file output */
  
  int main(int argc, char **argv)
  
  {
  
      OutputStream video_st = { 0 }, audio_st = { 0 };
  
      const char *filename;
  
      AVOutputFormat *fmt;
  
      AVFormatContext *oc;
  
      AVCodec *video_codec, *enc_codec;
  
      int ret;
  
      int have_video = 0;
  
      int encode_video = 0;
  
      AVDictionary *opt = NULL;
  
      int i;
  
      av_log_set_level(AV_LOG_DEBUG); //Debug flag
  
  
  
      if (argc &lt; 2) {
  
          printf("usage: %s output_file\n"
  
                 "API example program to output a media file with libavformat.\n"
  
                 "This program generates a synthetic audio and video stream, encodes and\n"
  
                 "muxes them into a file named output_file.\n"
  
                 "The output format is automatically guessed according to the file extension.\n"
  
                 "Raw images can also be output by using '%%d' in the filename.\n"
  
                 "\n", argv[0]);
  
          return 1;
  
      }
  
  
  
      filename = argv[1];
  
      for (i = 2; i+1 &lt; argc; i+=2) {
  
          if (!strcmp(argv[i], "-flags") || !strcmp(argv[i], "-fflags"))
  
              av_dict_set(&amp;opt, argv[i]+1, argv[i+1], 0);
  
      }
  
      //HW Encoding
  
      ret = av_hwdevice_ctx_create(&amp;hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, NULL, NULL, 0);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Failed to create a VAAPI device. Error code: %s\n", av_err2str(ret));
  
          return -1;
  
      }
  
      if (!(video_codec = avcodec_find_encoder_by_name("h264_vaapi"))) {
  
          printf(stderr, "Could not find encoder h264_vaapi");
  
          ret = -1;
  
      }
  
      /* allocate the output media context */
  
      avformat_alloc_output_context2(&amp;oc, NULL, NULL, filename);
  
      if (!oc) {
  
          printf("Could not deduce output format from file extension: using MPEG.\n");
  
          avformat_alloc_output_context2(&amp;oc, NULL, "mpeg", filename);
  
      }
  
      if (!oc)
  
          return 1;
  
  
  
      fmt = oc->oformat;
  
      /* Add the audio and video streams using the default format codecs
  
       * and initialize the codecs. */
  
      if (fmt->video_codec != AV_CODEC_ID_NONE) {
  
          add_stream(&amp;video_st, oc, &amp;video_codec, fmt->video_codec);
  
          have_video = 1;
  
          encode_video = 1;
  
      }
  
  
  
      /* Now that all the parameters are set, we can open the audio and
  
       * video codecs and allocate the necessary encode buffers. */
  
      if (have_video)
  
          open_video(oc, video_codec, &amp;video_st, opt);
  
      av_dump_format(oc, 0, filename, 1);
  
      /* open the output file, if needed */
  
      if (!(fmt->flags &amp; AVFMT_NOFILE)) {
  
          ret = avio_open(&amp;oc->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret &lt; 0) {
  
              fprintf(stderr, "Could not open '%s': %s\n", filename,
  
                      av_err2str(ret));
  
              return 1;
  
          }
  
      }
  
  
  
      /* Write the stream header, if any. */
  
      ret = avformat_write_header(oc, &amp;opt);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Error occurred when opening output file: %s\n",
  
                  av_err2str(ret));
  
          return 1;
  
      }
  
      printf ("line #%d\n", __LINE__);
  
      while (encode_video) {
  
          /* select the stream to encode */
  
          if (encode_video &amp;&amp;
  
              (av_compare_ts(video_st.next_pts, video_st.enc->time_base,
  
                                              video_st.next_pts, video_st.enc->time_base) &lt;= 0)) {
  
              printf ("line #%d\n", __LINE__);
  
              encode_video = !write_video_frame(oc, &amp;video_st);
  
              printf ("line #%d\n", __LINE__);
  
          }
  
      }
  
      av_write_trailer(oc);
  
      /* Close each codec. */
  
      if (have_video)
  
          close_stream(oc, &amp;video_st);
  
      if (!(fmt->flags &amp; AVFMT_NOFILE))
  
          /* Close the output file. */
  
          avio_closep(&amp;oc->pb);
  
      /* free the stream */
  
      avformat_free_context(oc);
  
      av_buffer_unref(&amp;hw_device_ctx);
  
      return 0;
  
  }

• ffmpeg download mp3 in chunks slower than whole file

  6 août 2021, par loretoparisi

  I'm programmatically downloading in Python mp3 file's as wav chunks, seeking at position with ss and t with ffmpeg resulting in a sequence of ffmpeg commands

  


  ffmpeg -i https://file-examples-com.github.io/uploads/2017/11/file_example_MP3_5MG.mp3 -acodec pcm_s16le -ac 1 -ar 44100 -ss 0:08:55.780000 -t 0:01:00.000000 -sn -vn -y -f wav pipe:1
ffmpeg -i https://file-examples-com.github.io/uploads/2017/11/file_example_MP3_5MG.mp3 -acodec pcm_s16le -ac 1 -ar 44100 -ss -ss 0:09:55.780000 -t 0:01:00.000000 -sn -vn -y -f wav pipe:1
ffmpeg -i https://file-examples-com.github.io/uploads/2017/11/file_example_MP3_5MG.mp3 -acodec pcm_s16le -ac 1 -ar 44100 -ss -ss -ss 0:10:55.780000 -t 0:01:00.000000 -sn -vn -y -f wav pipe:1
...


  


  executed via concurrent.futures.ThreadPoolExecutor in this way :

  


  with concurrent.futures.ThreadPoolExecutor(max_workers=NTHREADS) as executor:
        for i,cmd in enumerate(process_list):
            futures.append(executor.submit(downloader.chunk_download,(cmd,i)))

        for future in concurrent.futures.as_completed(futures):
            try:
                completed.append(future.result())
            except Exception as e:print(e)
    completed.sort() 
    for k,c in enumerate(completed):
        if not k:
            waveform = c[1]
        else:
            waveform = np.append(waveform,c[1])


  


  where chunk_download is concat the chunks into the whole waveform

  


  def chunk_download(self,args):
        cmd=args[0]
        i=args[1]
        print('Downloading chunk n° %i' % i)

        print( ' '.join(cmd))
        process = subprocess.run(cmd,
                            stdout=subprocess.PIPE,
                            stderr=subprocess.PIPE,
                            bufsize=10**8)
        #buffer, stderr = process.communicate()
        buffer = process.stdout
        stderr = process.stderr
        print('chunk n° %i DOWNLOADED' % i)
        # convert to signal
        chunk_waveform = np.frombuffer(buffer=buffer, dtype=np.uint16, offset=8*44)
        chunk_waveform = chunk_waveform.astype(self.dtype)  
        print(len(chunk_waveform)/44100) 

        return i,chunk_waveform


  


  this works ok, but if I download the whole mp3, executing the command in cmd like :

  


  ffmpeg -i https://file-examples-com.github.io/uploads/2017/11/file_example_MP3_5MG.mp3 -acodec pcm_s16le -ac 1 -ar 44100 -sn -vn -y -f wav pipe:1


  


  It will take less time than the concurrent chunks download for the same file length, while I would expect the opposite. Could be this related to ffmpeg threading option (param --thread ?). If not, why the concurrent chunks download operation is slower ?

  


• c++ how to use lambdas to set ffmpeg's av_log_set_callback() to a member function ?

  13 février 2018, par Blake Senftner

  I’ve been researching how to use lambdas as callbacks, but I do not seem to be getting my syntax correct. I am working in C++ via Visual Studio 2013 Community, & I am pretty sure this type of lambda use is supported. I am working on a video library which is based on the FFMPEG libav libraries.

  The basic issue is the logging callback provided to library clients of FFMPEG’s libav. It has this calling structure :

  void logging_callback( void *ptr, int level, const char *fmt, va_list vargs  );

  This is fine for C or fine for C++ when the logging callback is a static member function, but I want to install a class member function, which needs the this parameter per the C++ nature of calling method functions.

  What I have so far looks like : (unrelated portions removed)

  class my_libav
  
  { 
  
     // logging messages callback for use by library client, any log messages generated 
  
     // by the library will be sent thru this to the lib client's logic:
  
     typedef void(*STREAM_LOGGING_CALLBACK_CB) (std::string msg, void* p_object);
  
  
  
     // my lib's logger has a void* param so clients can redirect to member functs easier
  
     void SetStreamLoggingCallback(STREAM_LOGGING_CALLBACK_CB p_stream_logger, void* p_object);
  
  
  
     // member function to be installed as FFMPEG's av_log_set_callback():
  
     void RedirectLoggingOutputs( void *ptr, int level, const char *fmt, va_list vargs );
  
  
  
     STREAM_LOGGING_CALLBACK_CB  mp_stream_logging_callback; // client's callback
  
     void*                       mp_stream_logging_object;   // client's data
  
  
  
  };
  
  
  
  void my_libav::SetStreamLoggingCallback(STREAM_LOGGING_CALLBACK_CB p_stream_logger, void* p_object)
  
  {
  
    mp_stream_logging_callback = p_stream_logger;
  
    mp_stream_logging_object = p_object;
  
  }
  
  
  
  void my_libav::RedirectLoggingOutputs(void *ptr, int level, const char *fmt, va_list vargs )
  
  {
  
    // logic that resolves the message and sends through client's callback
  
    // installed int mp_stream_logging_callback
  
  }
  
  
  
  my_libav::my_libav()
  
  {
  
    // this is the old static member function I deleted:
  
    // av_log_set_callback( &my_libav::logging_callback );
  
  
  
    // I tried using std::bind & placeholders, but this syntax is wrong too:
  
    // namespace ph = std::placeholders;
  
    // auto callback = std::bind( &my_libav::RedirectLoggingOutputs, this, ph::_1, ph::_2, ph::_3, ph::_4 );
  
    // 
  
    // av_log_set_callback( callback ); // <- 'callback' is not the correct type
  
  
  
    // this is my try at a lambda. I know that the *this* cannot be 
  
    // in the capture, but I don't know the right syntax to work around 
  
    // this issue:
  
    std::function 
  
          f2 = [this](void *ptr, int level, const char *fmt, va_list vargs ){
  
                          RedirectLoggingOutputs( ptr, level, fmt, vargs ); };
  
  
  
      av_log_set_callback( f2 ); // <- 'f2' is not the correct type, how to fix? 

  The syntax I am trying to fix is in the last 4 lines. What is the correct form ?