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  • FFmpeg not honoring bitrate for different containers ?

    19 mars 2013, par Haleeq Usman

    I am attempting to encode a mp4 video file into a flv video. Here is what I am doing :

    #include
    #include
    #include
    #include
    #include <libavcodec></libavcodec>avcodec.h>
    #include <libavformat></libavformat>avformat.h>

    #define STREAM_FRAME_RATE 30 /* 30 images/s */
    #define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */
    /**************************************************************/
    /* Add an output stream. */
    static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec,
           enum AVCodecID codec_id) {
       AVCodecContext *c;
       AVStream *st;
       /* find the encoder */
       *codec = avcodec_find_encoder(codec_id);
       if (!(*codec)) {
           fprintf(stderr, "Could not find encoder for &#39;%s&#39;\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_VIDEO:
           //avcodec_get_context_defaults3(c, *codec);
           c->codec_id = codec_id;
           c->bit_rate = 150 * 1000; //2314000;;
           //c->rc_max_rate = 150*1000;
           //c->rc_buffer_size = 150*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 &amp; AVFMT_GLOBALHEADER)
           c->flags |= CODEC_FLAG_GLOBAL_HEADER;
       return st;
    }
    /**************************************************************/
    /* video output */
    static AVFrame *frame;
    static AVPicture src_picture, dst_picture;
    static int frame_count;
    static void open_video(AVFormatContext *oc, AVCodec *codec, AVStream *st) {
       int ret;
       AVCodecContext *c = st->codec;
       /* open the codec */
       ret = avcodec_open2(c, codec, NULL);
       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 */
       frame = avcodec_alloc_frame();
       if (!frame) {
           fprintf(stderr, "Could not allocate video frame\n");
           exit(1);
       }
       /* Allocate the encoded raw picture. */
       ret = avpicture_alloc(&amp;dst_picture, c->pix_fmt, c->width, c->height);
       if (ret &lt; 0) {
           fprintf(stderr, "Could not allocate picture: %s\n", av_err2str(ret));
           exit(1);
       }
       /* If the output format is not YUV420P, then a temporary YUV420P
        * picture is needed too. It is then converted to the required
        * output format. */
       if (c->pix_fmt != AV_PIX_FMT_YUV420P) {
           ret = avpicture_alloc(&amp;src_picture, AV_PIX_FMT_YUV420P, c->width,
                   c->height);
           if (ret &lt; 0) {
               fprintf(stderr, "Could not allocate temporary picture: %s\n",
                       av_err2str(ret));
               exit(1);
           }
       }
       /* copy data and linesize picture pointers to frame */
       *((AVPicture *) frame) = dst_picture;
    }
    static void close_video(AVFormatContext *oc, AVStream *st) {
       avcodec_close(st->codec);
       av_free(src_picture.data[0]);
       av_free(dst_picture.data[0]);
       av_free(frame);
    }

    int main(int argc, char *argv[]) {
       AVFormatContext *pFormatCtx = NULL;
       int i, videoStream;
       AVCodecContext *pCodecCtx = NULL;
       AVCodec *pCodec;
       AVFrame *pFrame;
       AVPacket packet;
       int frameFinished;

       const char *filename;
       AVOutputFormat *fmt;
       AVFormatContext *oc;
       AVStream *video_st;
       AVCodec *video_codec;
       int ret;

       // Register all formats, codecs and network
       av_register_all();
       avcodec_register_all();
       avformat_network_init();

       // Open video file
       if (avformat_open_input(&amp;pFormatCtx, "input_file.mp4", NULL, NULL) != 0)
           return -1; // Couldn&#39;t open file

       // Retrieve stream information
       if (avformat_find_stream_info(pFormatCtx, NULL) &lt; 0)
           return -1; // Couldn&#39;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 &lt; pFormatCtx->nb_streams; i++)
           if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
               videoStream = i;
               break;
           }
       if (videoStream == -1)
           return -1; // Didn&#39;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) &lt; 0)
           return -1; // Could not open codec

       // Allocate video frame
       pFrame = avcodec_alloc_frame();

       // setup mux
       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;

       // Add the video streams using the default format codecs
       // and initialize the codecs.
       video_st = NULL;
       if (fmt->video_codec != AV_CODEC_ID_NONE) {
           video_st = add_stream(oc, &amp;video_codec, fmt->video_codec);
       }
       // Now that all the parameters are set, we can open the
       // video codec and allocate the necessary encode buffers.
       if (video_st)
           open_video(oc, video_codec, video_st);

       /* 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 &#39;%s&#39;: %s\n", filename,
                       av_err2str(ret));
               return 1;
           }
       }

       // dump output format
       av_dump_format(oc, 0, filename, 1);

       // Write the stream header, if any.
       ret = avformat_write_header(oc, NULL);
       if (ret &lt; 0) {
           fprintf(stderr, "Error occurred when opening output file: %s\n",
                   av_err2str(ret));
           return 1;
       }

       // Read frames, decode, and re-encode
       while (av_read_frame(pFormatCtx, &amp;packet) >= 0) {
           // Is this a packet from the video stream?
           if (packet.stream_index == videoStream) {
               // Decode video frame
               avcodec_decode_video2(pCodecCtx, pFrame, &amp;frameFinished, &amp;packet);

               // Did we get a video frame?
               if (frameFinished) {

                   AVFrame* newFrame = avcodec_alloc_frame(); // Initialize a new frame
                   int size = avpicture_get_size(video_st->codec->pix_fmt,
                           video_st->codec->width, video_st->codec->height);
                   uint8_t* picture_buf = av_malloc(size);

                   avpicture_fill((AVPicture *) newFrame, picture_buf,
                           video_st->codec->pix_fmt, video_st->codec->width,
                           video_st->codec->height);

                   // Copy only the frame content without any other disturbing
                   av_picture_copy((AVPicture*) newFrame, (AVPicture*) pFrame,
                           video_st->codec->pix_fmt, video_st->codec->width,
                           video_st->codec->height);

                   // encode the image
                   AVPacket pkt;
                   int got_output;
                   av_init_packet(&amp;pkt);
                   pkt.data = NULL; // packet data will be allocated by the encoder
                   pkt.size = 0;

                   /* Setting newFrame->pts this way produces the error &#39;non-strictly-monotonic PTS&#39; */
                   //if(newFrame->pts != AV_NOPTS_VALUE)
                   //newFrame->pts = av_rescale_q(newFrame->pts, video_st->time_base, video_st->codec->time_base);

                   // Setting newFrame->pts this does not produce &#39;non-strictly-monotonic PTS&#39;
                   newFrame->pts = frame_count;

                   ret = avcodec_encode_video2(video_st->codec, &amp;pkt, newFrame, &amp;got_output);
                   if (ret &lt; 0) {
                       fprintf(stderr, "Error encoding video frame: %s\n", av_err2str(ret));
                       exit(1);
                   }

                   if (got_output) {
                       if (video_st->codec->coded_frame->key_frame)
                       pkt.flags |= AV_PKT_FLAG_KEY;
                       pkt.stream_index = video_st->index;

                       if (pkt.pts != AV_NOPTS_VALUE)
                           pkt.pts = av_rescale_q(pkt.pts,
                                   video_st->codec->time_base,
                                   video_st->time_base);
                       if (pkt.dts != AV_NOPTS_VALUE)
                           pkt.dts = av_rescale_q(pkt.dts,
                                   video_st->codec->time_base,
                                   video_st->time_base);

                       // Write the compressed frame to the media file.
                       ret = av_interleaved_write_frame(oc, &amp;pkt);
                   } else {
                       ret = 0;
                   }
                   if (ret != 0) {
                       fprintf(stderr, "Error while writing video frame: %s\n",
                               av_err2str(ret));
                       exit(1);
                   }

                   fprintf(stderr, "encoded frame #%d\n", frame_count);
                   frame_count++;
                   av_free(picture_buf);
                   av_free_packet(&amp;pkt);
               }
           }

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

       /* Write the trailer, if any. The trailer must be written before you
        * close the CodecContexts open when you wrote the header; otherwise
        * av_write_trailer() may try to use memory that was freed on
        * av_codec_close(). */
       av_write_trailer(oc);

       /* Close video encoder (codec). */
       if (video_st)
           close_video(oc, video_st);
       // Free the streams.
       for (i = 0; i &lt; oc->nb_streams; i++) {
           av_freep(&amp;oc->streams[i]->codec);
           av_freep(&amp;oc->streams[i]);
       }
       if (!(fmt->flags &amp; AVFMT_NOFILE))
           /* Close the output file. */
           avio_close(oc->pb);
       /* free the stream */
       av_free(oc);

       // Free the YUV frame holding decoded frame
       av_free(pFrame);

       // Close the decoder (codec)
       avcodec_close(pCodecCtx);

       // Close the input video file
       avformat_close_input(&amp;pFormatCtx);

       return 0;
    }

    If I change the output format to an mp4, mov, or f4v by changing :

    // setup mux (FLV OUTPUT)
    filename = "output_file.flv";
    fmt = av_guess_format("flv", filename, NULL);
    if (fmt == NULL) {
       printf("Could not guess format.\n");
       return -1;
    }

    to

    // setup mux (MP4 OUTPUT)
    filename = "output_file.mp4";
    fmt = av_guess_format("mp4", filename, NULL);
    if (fmt == NULL) {
       printf("Could not guess format.\n");
       return -1;
    }

    Then the bitrate is honored. Here is the output of running with a mp4 output

    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from &#39;input_file.mp4&#39;:
     Metadata:
       major_brand     : mp42
       minor_version   : 0
       compatible_brands: isomavc1mp42
       creation_time   : 2010-02-09 19:11:10
     Duration: 00:04:31.80, start: 0.000000, bitrate: 2314 kb/s
       Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s
       Metadata:
         creation_time   : 2010-02-09 19:11:10
         handler_name    : (C) 2007 Google Inc. v08.13.2007.
       Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 2186 kb/s, 30 fps, 30 tbr, 30k tbn, 60 tbc
       Metadata:
         creation_time   : 2010-02-09 19:11:10
         handler_name    : (C) 2007 Google Inc. v08.13.2007.
    [libx264 @ 02268b80] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 AVX
    [libx264 @ 02268b80] profile High, level 3.1
    [libx264 @ 02268b80] 264 - core 129 r2230 1cffe9f - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deb
    lock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chro
    ma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
    b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=12 keyint_min=1 scenecut=40 intra_refresh=0 rc_lookahead=12 rc=abr mbtree=1 bitrate=150 ratetol=1.0 qco
    mp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
    Output #0, mp4, to &#39;output_file.mp4&#39;:
       Stream #0:0: Video: h264, yuv420p, 1280x720, q=-1--1, 150 kb/s, 90k tbn, 30 tbc
    encoded frame #0
    encoded frame #1
    encoded frame #2
    encoded frame #3
    .
    .
    .
    encoded frame #8142
    encoded frame #8143
    encoded frame #8144
    encoded frame #8145
    [libx264 @ 02174240] frame I:771   Avg QP:47.71  size:  2739
    [libx264 @ 02174240] frame P:5083  Avg QP:50.05  size:   833
    [libx264 @ 02174240] frame B:2264  Avg QP:48.16  size:    91
    [libx264 @ 02174240] consecutive B-frames: 59.6%  6.4%  9.0% 24.9%
    [libx264 @ 02174240] mb I  I16..4: 34.0% 65.8%  0.2%
    [libx264 @ 02174240] mb P  I16..4:  6.8%  3.0%  0.0%  P16..4:  8.5%  0.4%  1.7%  0.0%  0.0%    skip:79.6%
    [libx264 @ 02174240] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  1.8%  0.0%  0.0%  direct: 0.0%  skip:98.2%  L0:23.6% L1:76.4% BI: 0.0%
    [libx264 @ 02174240] final ratefactor: 57.62
    [libx264 @ 02174240] 8x8 transform intra:52.1% inter:98.5%
    [libx264 @ 02174240] coded y,uvDC,uvAC intra: 3.1% 14.0% 0.2% inter: 0.1% 0.4% 0.0%
    [libx264 @ 02174240] i16 v,h,dc,p: 69% 23%  4%  4%
    [libx264 @ 02174240] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23%  6% 68%  1%  1%  1%  1%  0%  0%
    [libx264 @ 02174240] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 41% 18% 18%  4%  4%  5%  3%  3%  3%
    [libx264 @ 02174240] i8c dc,h,v,p: 98%  1%  1%  0%
    [libx264 @ 02174240] Weighted P-Frames: Y:2.1% UV:1.2%
    [libx264 @ 02174240] ref P L0: 72.4%  0.8% 19.1%  7.6%  0.1%
    [libx264 @ 02174240] ref B L0: 89.8%  9.1%  1.2%
    [libx264 @ 02174240] ref B L1: 96.2%  3.8%
    [libx264 @ 02174240] kb/s:193.62

    The final file size of output_file.mp4 is about 6.5MB and using ffplay, I notice that bitrate was honored. Of course the quality itself shows.

    Here is the output of running with a flv output :

    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from &#39;input_file.mp4&#39;:
     Metadata:
       major_brand     : mp42
       minor_version   : 0
       compatible_brands: isomavc1mp42
       creation_time   : 2010-02-09 19:11:10
     Duration: 00:04:31.80, start: 0.000000, bitrate: 2314 kb/s
       Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s
       Metadata:
         creation_time   : 2010-02-09 19:11:10
         handler_name    : (C) 2007 Google Inc. v08.13.2007.
       Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 2186 kb/s, 30 fps, 30 tbr, 30k tbn, 60 tbc
       Metadata:
         creation_time   : 2010-02-09 19:11:10
         handler_name    : (C) 2007 Google Inc. v08.13.2007.
    Output #0, flv, to &#39;output_file.flv&#39;:
       Stream #0:0: Video: flv1, yuv420p, 1280x720, q=2-31, 150 kb/s, 90k tbn, 30 tbc
    encoded frame #0
    encoded frame #1
    encoded frame #2
    encoded frame #3
    .
    .
    .
    encoded frame #8142
    encoded frame #8143
    encoded frame #8144
    encoded frame #8145

    I noticed that the bitrate is honored as long as the container is a mp4, mov, f4v, or something similar. If I try flv, wmv, or other different containers, then the bitrate is not honored. Also, the bitrate that is automatically set for wmv is different from that of flv. I am not sure what I am doing wrong. I suspect it has to do with the pts, however, I cannot find a solution :(.

  • Auto detect rotation and rotate video accordingly with mencoder, handbrake cli or ffmpeg

    29 décembre 2012, par Andrew Barraclough

    I have found questions on rotating videos with mencoder and ffmpeg however I am after a fully automated solution.

    Can anybody help with this.

    I want to

    • Detect the video orientation
    • Rotate if needed
    • Reset the meta data on the video (otherwise watching on a iOS device will cause unwanted rotation)
    • Save video in desired format

    The reason for this is a wish to use the processed videos in a HTML5 video player. If I rotate without resetting the meta data iOS devices will read the meta and further rotate causing the video to be out by another 90 degrees.