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  • How to write NALs produced by x264_encoder_encode() using ffmpeg av_interleaved_write_frame()

    21 janvier 2013, par Haleeq Usman

    I have been trying to produce a "flv" video file in the following sequence :

    av_register_all();

    // Open video file
    if (avformat_open_input(&pFormatCtx, "6.mp4", NULL, NULL) != 0)
       return -1; // Couldn't open file

    // Retrieve stream information
    if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
       return -1; // Couldn't find stream information

    // Dump information about file onto standard error
    av_dump_format(pFormatCtx, 0, "input_file.mp4", 0);

    // Find the first video stream
    videoStream = -1;
    for (i = 0; i < pFormatCtx->nb_streams; i++)
       if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
           videoStream = i;
           break;
       }
    if (videoStream == -1)
       return -1; // Didn't find a video stream

    // Get a pointer to the codec context for the video stream
    pCodecCtx = pFormatCtx->streams[videoStream]->codec;

    // Find the decoder for the video stream
    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
    if (pCodec == NULL) {
       fprintf(stderr, "Unsupported codec!\n");
       return -1; // Codec not found
    }
    // Open codec
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
       return -1; // Could not open codec

    // Allocate video frame
    pFrame = avcodec_alloc_frame();

    // Allocate video frame
    pFrame = avcodec_alloc_frame();

    // Allocate an AVFrame structure
    pFrameYUV420 = avcodec_alloc_frame();
    if (pFrameYUV420 == NULL)
       return -1;

    // Determine required buffer size and allocate buffer
    numBytes = avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
    buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));

    // Assign appropriate parts of buffer to image planes in pFrameYUV420
    // Note that pFrameYUV420 is an AVFrame, but AVFrame is a superset of AVPicture
    avpicture_fill((AVPicture *) pFrameRGB, buffer, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);

    // Setup scaler
    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, SWS_BILINEAR, 0, 0, 0);
    if (img_convert_ctx == NULL) {
       fprintf(stderr, "Cannot initialize the conversion context!\n");
       exit(1);
    }

    // Setup encoder/muxing now
    filename = "output_file.flv";
    fmt = av_guess_format("flv", filename, NULL);
    if (fmt == NULL) {
       printf("Could not guess format.\n");
       return -1;
    }
    /* allocate the output media context */
    oc = avformat_alloc_context();
    if (oc == NULL) {
       printf("could not allocate context.\n");
       return -1;
    }
    oc->oformat = fmt;
    snprintf(oc->filename, sizeof(oc->filename), "%s", filename);

    video_st = NULL;
    if (fmt->video_codec != AV_CODEC_ID_NONE) {
       video_st = add_stream(oc, &video_codec, fmt->video_codec);
    }

    // Let's see some information about our format
    av_dump_format(oc, 0, filename, 1);

    /* open the output file, if needed */
    if (!(fmt->flags & AVFMT_NOFILE)) {
       ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
       if (ret < 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, NULL);
    if (ret < 0) {
       fprintf(stderr, "Error occurred when opening output file: %s\n", av_err2str(ret));
       return 1;
    }

    // Setup x264 params
    x264_param_t param;
    x264_param_default_preset(&param, "veryfast", "zerolatency");
    param.i_threads = 1;
    param.i_width = video_st->codec->width;
    param.i_height = video_st->codec->height;
    param.i_fps_num = STREAM_FRAME_RATE; // 30 fps, same as video
    param.i_fps_den = 1;
    // Intra refres:
    param.i_keyint_max = STREAM_FRAME_RATE;
    param.b_intra_refresh = 1;
    // Rate control:
    param.rc.i_rc_method = X264_RC_CRF;
    param.rc.f_rf_constant = 25;
    param.rc.f_rf_constant_max = 35;
    // For streaming:
    param.b_repeat_headers = 1;
    param.b_annexb = 1;
    x264_param_apply_profile(&param, "baseline");

    x264_t* encoder = x264_encoder_open(&param);
    x264_picture_t pic_in, pic_out;
    x264_picture_alloc(&pic_in, X264_CSP_I420, video_st->codec->width, video_st->codec->height);

    x264_nal_t* nals;
    int i_nals;

    // The loop:
    // 1. Read frames
    // 2. Decode the frame
    // 3. Attempt to re-encode using x264
    // 4. Write the x264 encoded frame using av_interleaved_write_frame
    while (av_read_frame(pFormatCtx, &packet) >= 0) {
       // Is this a packet from the video stream?
       if (packet.stream_index == videoStream) {
           // Decode video frame
           avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);

           // Did we get a video frame?
           if (frameFinished) {
               sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pic_in.img.plane, pic_in.img.i_stride);
               int frame_size = x264_encoder_encode(encoder, &nals, &i_nals, &pic_in, &pic_out);

               if (frame_size >= 0) {
                   if (i_nals < 0)
                       printf("invalid frame size: %d\n", i_nals);
                   // write out NALs
                   for (i = 0; i < i_nals; i++) {
                       // initalize a packet
                       AVPacket p;
                       av_init_packet(&p);
                       p.data = nals[i].p_payload;
                       p.size = nals[i].i_payload;
                       p.stream_index = video_st->index;
                       p.flags = AV_PKT_FLAG_KEY;
                       p.pts = AV_NOPTS_VALUE;
                       p.dts = AV_NOPTS_VALUE;
                       ret = av_interleaved_write_frame(oc, &p);
                   }
               }
               printf("encoded frame #%d\n", frame_count);
               frame_count++;
           }
       }

       // Free the packet that was allocated by av_read_frame
       av_free_packet(&packet);
    }

    // Now we free up resources used/close codecs, and finally close our program.

    Here is the implementation for the add_stream() function :

    /* Add an output stream. */
    static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec, enum AVCodecID codec_id) {
       AVCodecContext *c;
       AVStream *st;
       int r;
       /* find the encoder */
       *codec = avcodec_find_encoder(codec_id);
       if (!(*codec)) {
           fprintf(stderr, "Could not find encoder for '%s'\n",
                   avcodec_get_name(codec_id));
           exit(1);
       }
       st = avformat_new_stream(oc, *codec);
       if (!st) {
           fprintf(stderr, "Could not allocate stream\n");
           exit(1);
       }
       st->id = oc->nb_streams - 1;
       c = st->codec;
       switch ((*codec)->type) {
       case AVMEDIA_TYPE_AUDIO:
           st->id = 1;
           c->sample_fmt = AV_SAMPLE_FMT_FLTP;
           c->bit_rate = 64000;
           c->sample_rate = 44100;
           c->channels = 2;
           break;
       case AVMEDIA_TYPE_VIDEO:
           avcodec_get_context_defaults3(c, *codec);
           c->codec_id = codec_id;
           c->bit_rate = 500*1000;
           //c->rc_min_rate = 500*1000;
           //c->rc_max_rate = 500*1000;
           //c->rc_buffer_size = 500*1000;
           /* Resolution must be a multiple of two. */
           c->width = 1280;
           c->height = 720;
           /* timebase: This is the fundamental unit of time (in seconds) in terms
            * of which frame timestamps are represented. For fixed-fps content,
            * timebase should be 1/framerate and timestamp increments should be
            * identical to 1. */
           c->time_base.den = STREAM_FRAME_RATE;
           c->time_base.num = 1;
           c->gop_size = 12; /* emit one intra frame every twelve frames at most */
           c->pix_fmt = STREAM_PIX_FMT;
           if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
               /* just for testing, we also add B frames */
               c->max_b_frames = 2;
           }
           if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
               /* Needed to avoid using macroblocks in which some coeffs overflow.
                * This does not happen with normal video, it just happens here as
                * the motion of the chroma plane does not match the luma plane. */
               c->mb_decision = 2;
           }
           break;
       default:
           break;
       }
       /* Some formats want stream headers to be separate. */
       if (oc->oformat->flags & AVFMT_GLOBALHEADER)
           c->flags |= CODEC_FLAG_GLOBAL_HEADER;
       return st;
    }

    After the encoding is complete, I check the output file output_file.flv. I notice it's size is very large : 101MB and it does not play. If I use ffmpeg to decode/encode the input file, then I get an output file about 83MB in size (which is about the same size as the original .mp4 file used as input). Also, the 83MB output from just using ffmpeg C api, as opposed to using x264 for the encoding step, plays just fine. Does anyone know where I am going wrong ? I have tried researching this for a few days now but with no luck :(. I feel that I am close to making it work, however, I just cannot figure out what I am doing wrong. Thank you !

  • How to write NALs produced by x264_encoder_encode() using ffmpeg av_interleaved_write_frame()

    21 janvier 2013, par Haleeq Usman

    I have been trying to produce a "flv" video file in the following sequence :

    av_register_all();

    // Open video file
    if (avformat_open_input(&pFormatCtx, "6.mp4", NULL, NULL) != 0)
       return -1; // Couldn't open file

    // Retrieve stream information
    if (avformat_find_stream_info(pFormatCtx, NULL) < 0)
       return -1; // Couldn't find stream information

    // Dump information about file onto standard error
    av_dump_format(pFormatCtx, 0, "input_file.mp4", 0);

    // Find the first video stream
    videoStream = -1;
    for (i = 0; i < pFormatCtx->nb_streams; i++)
       if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
           videoStream = i;
           break;
       }
    if (videoStream == -1)
       return -1; // Didn't find a video stream

    // Get a pointer to the codec context for the video stream
    pCodecCtx = pFormatCtx->streams[videoStream]->codec;

    // Find the decoder for the video stream
    pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
    if (pCodec == NULL) {
       fprintf(stderr, "Unsupported codec!\n");
       return -1; // Codec not found
    }
    // Open codec
    if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
       return -1; // Could not open codec

    // Allocate video frame
    pFrame = avcodec_alloc_frame();

    // Allocate video frame
    pFrame = avcodec_alloc_frame();

    // Allocate an AVFrame structure
    pFrameYUV420 = avcodec_alloc_frame();
    if (pFrameYUV420 == NULL)
       return -1;

    // Determine required buffer size and allocate buffer
    numBytes = avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
    buffer = (uint8_t *) av_malloc(numBytes * sizeof(uint8_t));

    // Assign appropriate parts of buffer to image planes in pFrameYUV420
    // Note that pFrameYUV420 is an AVFrame, but AVFrame is a superset of AVPicture
    avpicture_fill((AVPicture *) pFrameRGB, buffer, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);

    // Setup scaler
    img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, SWS_BILINEAR, 0, 0, 0);
    if (img_convert_ctx == NULL) {
       fprintf(stderr, "Cannot initialize the conversion context!\n");
       exit(1);
    }

    // Setup encoder/muxing now
    filename = "output_file.flv";
    fmt = av_guess_format("flv", filename, NULL);
    if (fmt == NULL) {
       printf("Could not guess format.\n");
       return -1;
    }
    /* allocate the output media context */
    oc = avformat_alloc_context();
    if (oc == NULL) {
       printf("could not allocate context.\n");
       return -1;
    }
    oc->oformat = fmt;
    snprintf(oc->filename, sizeof(oc->filename), "%s", filename);

    video_st = NULL;
    if (fmt->video_codec != AV_CODEC_ID_NONE) {
       video_st = add_stream(oc, &video_codec, fmt->video_codec);
    }

    // Let's see some information about our format
    av_dump_format(oc, 0, filename, 1);

    /* open the output file, if needed */
    if (!(fmt->flags & AVFMT_NOFILE)) {
       ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
       if (ret < 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, NULL);
    if (ret < 0) {
       fprintf(stderr, "Error occurred when opening output file: %s\n", av_err2str(ret));
       return 1;
    }

    // Setup x264 params
    x264_param_t param;
    x264_param_default_preset(&param, "veryfast", "zerolatency");
    param.i_threads = 1;
    param.i_width = video_st->codec->width;
    param.i_height = video_st->codec->height;
    param.i_fps_num = STREAM_FRAME_RATE; // 30 fps, same as video
    param.i_fps_den = 1;
    // Intra refres:
    param.i_keyint_max = STREAM_FRAME_RATE;
    param.b_intra_refresh = 1;
    // Rate control:
    param.rc.i_rc_method = X264_RC_CRF;
    param.rc.f_rf_constant = 25;
    param.rc.f_rf_constant_max = 35;
    // For streaming:
    param.b_repeat_headers = 1;
    param.b_annexb = 1;
    x264_param_apply_profile(&param, "baseline");

    x264_t* encoder = x264_encoder_open(&param);
    x264_picture_t pic_in, pic_out;
    x264_picture_alloc(&pic_in, X264_CSP_I420, video_st->codec->width, video_st->codec->height);

    x264_nal_t* nals;
    int i_nals;

    // The loop:
    // 1. Read frames
    // 2. Decode the frame
    // 3. Attempt to re-encode using x264
    // 4. Write the x264 encoded frame using av_interleaved_write_frame
    while (av_read_frame(pFormatCtx, &packet) >= 0) {
       // Is this a packet from the video stream?
       if (packet.stream_index == videoStream) {
           // Decode video frame
           avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);

           // Did we get a video frame?
           if (frameFinished) {
               sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pic_in.img.plane, pic_in.img.i_stride);
               int frame_size = x264_encoder_encode(encoder, &nals, &i_nals, &pic_in, &pic_out);

               if (frame_size >= 0) {
                   if (i_nals < 0)
                       printf("invalid frame size: %d\n", i_nals);
                   // write out NALs
                   for (i = 0; i < i_nals; i++) {
                       // initalize a packet
                       AVPacket p;
                       av_init_packet(&p);
                       p.data = nals[i].p_payload;
                       p.size = nals[i].i_payload;
                       p.stream_index = video_st->index;
                       p.flags = AV_PKT_FLAG_KEY;
                       p.pts = AV_NOPTS_VALUE;
                       p.dts = AV_NOPTS_VALUE;
                       ret = av_interleaved_write_frame(oc, &p);
                   }
               }
               printf("encoded frame #%d\n", frame_count);
               frame_count++;
           }
       }

       // Free the packet that was allocated by av_read_frame
       av_free_packet(&packet);
    }

    // Now we free up resources used/close codecs, and finally close our program.

    Here is the implementation for the add_stream() function :

    /* Add an output stream. */
    static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec, enum AVCodecID codec_id) {
       AVCodecContext *c;
       AVStream *st;
       int r;
       /* find the encoder */
       *codec = avcodec_find_encoder(codec_id);
       if (!(*codec)) {
           fprintf(stderr, "Could not find encoder for '%s'\n",
                   avcodec_get_name(codec_id));
           exit(1);
       }
       st = avformat_new_stream(oc, *codec);
       if (!st) {
           fprintf(stderr, "Could not allocate stream\n");
           exit(1);
       }
       st->id = oc->nb_streams - 1;
       c = st->codec;
       switch ((*codec)->type) {
       case AVMEDIA_TYPE_AUDIO:
           st->id = 1;
           c->sample_fmt = AV_SAMPLE_FMT_FLTP;
           c->bit_rate = 64000;
           c->sample_rate = 44100;
           c->channels = 2;
           break;
       case AVMEDIA_TYPE_VIDEO:
           avcodec_get_context_defaults3(c, *codec);
           c->codec_id = codec_id;
           c->bit_rate = 500*1000;
           //c->rc_min_rate = 500*1000;
           //c->rc_max_rate = 500*1000;
           //c->rc_buffer_size = 500*1000;
           /* Resolution must be a multiple of two. */
           c->width = 1280;
           c->height = 720;
           /* timebase: This is the fundamental unit of time (in seconds) in terms
            * of which frame timestamps are represented. For fixed-fps content,
            * timebase should be 1/framerate and timestamp increments should be
            * identical to 1. */
           c->time_base.den = STREAM_FRAME_RATE;
           c->time_base.num = 1;
           c->gop_size = 12; /* emit one intra frame every twelve frames at most */
           c->pix_fmt = STREAM_PIX_FMT;
           if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
               /* just for testing, we also add B frames */
               c->max_b_frames = 2;
           }
           if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
               /* Needed to avoid using macroblocks in which some coeffs overflow.
                * This does not happen with normal video, it just happens here as
                * the motion of the chroma plane does not match the luma plane. */
               c->mb_decision = 2;
           }
           break;
       default:
           break;
       }
       /* Some formats want stream headers to be separate. */
       if (oc->oformat->flags & AVFMT_GLOBALHEADER)
           c->flags |= CODEC_FLAG_GLOBAL_HEADER;
       return st;
    }

    After the encoding is complete, I check the output file output_file.flv. I notice it's size is very large : 101MB and it does not play. If I use ffmpeg to decode/encode the input file, then I get an output file about 83MB in size (which is about the same size as the original .mp4 file used as input). Also, the 83MB output from just using ffmpeg C api, as opposed to using x264 for the encoding step, plays just fine. Does anyone know where I am going wrong ? I have tried researching this for a few days now but with no luck :(. I feel that I am close to making it work, however, I just cannot figure out what I am doing wrong. Thank you !

  • FFMPEG text file [migrated]

    23 décembre 2012, par user872387

    I am giving the input file in the command line like this :

    ffmpeg -i catch.flv.

    The information about the file such as resolution, frame rate, bit rate etc is displayed in the terminal. I want this information to be stored as a (.txt) file. I have tried ffmpeg -i catch.flv > catch.txt. The .txt file was created successfully but the information is not stored in it. Could someone please help ?