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  • libavcodec/libx264 do not produce B-frames

    6 novembre 2013, par Rob Schmidt

    I am writing an application in C++ that uses libavcodec with libx264 to encode video. However, the encoded data ended up being much larger than I expected. I analyzed the results and discovered that my encoding never produced B-frames, only I- and P-frames.

    I created a standalone utility based on the ffmpeg source code and examples to test my encoder setup. It reads in an H.264 file, re-encodes the decoded frames, and outputs the result to a file using the ITU H.264 Annex B format. I also used ffmpeg to perform the same operation so I could compare against a known good implementation. My utility never outputs B-frames whereas ffmpeg does.

    I have since tried to figure out what ffmpeg does that my code doesn’t. I first tried manually specifying encoder settings related to B-frames. This had no effect.

    I then tried running both ffmpeg and my utility under gdb and comparing the contents of the AVStream, AVCodecContext, and X264Context prior to opening the encoder and manually setting any fields that appeared different. Even with identical settings, I still only produce I- and P-frames.

    Finally, I thought that perhaps the problem was with my timestamp handling. I reworked my test utility to mimic the pipeline used by ffmpeg and to output timestamp debugging output like ffmpeg does. Even with my timestamps identical to ffmpeg’s I still get no B-frames.

    At this point I don’t know what else to try. When I run ffmpeg, I run it with the command line below. Note that aside from the "superfast" preset, I pretty much use the default values.

    ffmpeg -v debug -i ~/annexb.264 -codec:v libx264 -preset superfast -g 30 -f h264 ./out.264

    The code that configures the encoder is listed below. It specifies the "superfast" preset too.

    static AVStream *add_video_stream(AVFormatContext *output_ctx, AVCodec **output_codec, enum AVCodecID codec_id)
    
{
    
    *output_codec = avcodec_find_encoder(codec_id);
    
    if (*output_codec == NULL) {
    
        printf("Could not find encoder for '%s' (%d)\n", avcodec_get_name(codec_id), codec_id);
    
        return NULL;
    
    }
    

    
    AVStream *output_stream = avformat_new_stream(output_ctx, *output_codec);
    
    if (output_stream == NULL) {
    
        printf("Could not create video stream.\n");
    
        return NULL;
    
    }
    
    output_stream->id = output_ctx->nb_streams - 1;
    
    AVCodecContext *codec_ctx = output_stream->codec;
    

    
    avcodec_get_context_defaults3(codec_ctx, *output_codec);
    

    
    codec_ctx->width = 1280;
    
    codec_ctx->height = 720;
    

    
    codec_ctx->time_base.den = 15000;
    
    codec_ctx->time_base.num = 1001;
    

    
/*    codec_ctx->gop_size = 30;*/
    
    codec_ctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
    

    
    // try to force B-frame output
    
/*    codec_ctx->max_b_frames = 3;*/
    
/*    codec_ctx->b_frame_strategy = 2;*/
    

    
    output_stream->sample_aspect_ratio.num = 1;
    
    output_stream->sample_aspect_ratio.den = 1;
    

    
    codec_ctx->sample_aspect_ratio.num = 1;
    
    codec_ctx->sample_aspect_ratio.den = 1;
    

    
    codec_ctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
    

    
    codec_ctx->bits_per_raw_sample = 8;
    

    
    if ((output_ctx->oformat->flags & AVFMT_GLOBALHEADER) != 0) {
    
        codec_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
    
    }
    

    
    return output_stream;
    
}
    

    

    
int main(int argc, char **argv)
    
{
    
    // ... open input file 
    

    
    avformat_alloc_output_context2(&output_ctx, NULL, "h264", output_path);
    
    if (output_ctx == NULL) {
    
        fprintf(stderr, "Unable to allocate output context.\n");
    
        return 1;
    
    } 
    

    
    AVCodec *output_codec = NULL;
    
    output_stream = add_video_stream(output_ctx, &output_codec, output_ctx->oformat->video_codec);
    
    if (output_stream == NULL) {
    
        fprintf(stderr, "Error adding video stream to output context.\n");
    
        return 1;
    
    }
    
    encode_ctx = output_stream->codec;
    

    
    // seems to have no effect
    
#if 0
    
    if (decode_ctx->extradata_size != 0) {
    
        size_t extradata_size = decode_ctx->extradata_size;
    
        printf("extradata_size: %zu\n", extradata_size);
    
        encode_ctx->extradata = av_mallocz(extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
    
        memcpy(encode_ctx->extradata, decode_ctx->extradata, extradata_size);
    
        encode_ctx->extradata_size = extradata_size;
    
    }
    
#endif // 0
    

    
    AVDictionary *opts = NULL;
    
    av_dict_set(&opts, "preset", "superfast", 0);
    
    // av_dict_set(&opts, "threads", "auto", 0); // seems to have no effect
    

    
    ret = avcodec_open2(encode_ctx, output_codec, &opts);
    
    if (ret < 0) {
    
        fprintf(stderr, "Unable to open output video cocec: %s\n", av_err2str(ret));
    
        return 1;
    
    }
    

    
    // ... decoding/encoding loop, clean up, etc.
    

    
    return 0;
    
}

    My test utility produces the following debug output in which you can see there are no B-frames produced :

    [libx264 @ 0x1b8c9c0] using mv_range_thread = 56
    
[libx264 @ 0x1b8c9c0] using SAR=1/1
    
[libx264 @ 0x1b8c9c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
    
[libx264 @ 0x1b8c9c0] profile High, level 3.1
    
Output #0, h264, to './out.264':
    
    Stream #0:0, 0, 1/90000: Video: h264, yuvj420p, 1280x720 [SAR 1:1 DAR 16:9], 1001/15000, q=-1--1, 90k tbn, 14.99 tbc
    

    
<snip>
    

    
[libx264 @ 0x1b8c9c0] frame=   0 QP=17.22 NAL=3 Slice:I Poc:0   I:3600 P:0    SKIP:0    size=122837 bytes
    
[libx264 @ 0x1b8c9c0] frame=   1 QP=18.03 NAL=2 Slice:P Poc:2   I:411  P:1825 SKIP:1364 size=25863 bytes
    
[libx264 @ 0x1b8c9c0] frame=   2 QP=17.03 NAL=2 Slice:P Poc:4   I:369  P:2159 SKIP:1072 size=37880 bytes
    
[libx264 @ 0x1b8c9c0] frame=   3 QP=16.90 NAL=2 Slice:P Poc:6   I:498  P:2330 SKIP:772  size=50509 bytes
    
[libx264 @ 0x1b8c9c0] frame=   4 QP=16.68 NAL=2 Slice:P Poc:8   I:504  P:2233 SKIP:863  size=50791 bytes
    
[libx264 @ 0x1b8c9c0] frame=   5 QP=16.52 NAL=2 Slice:P Poc:10  I:513  P:2286 SKIP:801  size=51820 bytes
    
[libx264 @ 0x1b8c9c0] frame=   6 QP=16.49 NAL=2 Slice:P Poc:12  I:461  P:2293 SKIP:846  size=51311 bytes
    
[libx264 @ 0x1b8c9c0] frame=   7 QP=16.65 NAL=2 Slice:P Poc:14  I:476  P:2287 SKIP:837  size=51196 bytes
    
[libx264 @ 0x1b8c9c0] frame=   8 QP=16.66 NAL=2 Slice:P Poc:16  I:508  P:2240 SKIP:852  size=51577 bytes
    
[libx264 @ 0x1b8c9c0] frame=   9 QP=16.55 NAL=2 Slice:P Poc:18  I:477  P:2278 SKIP:845  size=51531 bytes
    
[libx264 @ 0x1b8c9c0] frame=  10 QP=16.67 NAL=2 Slice:P Poc:20  I:517  P:2233 SKIP:850  size=51946 bytes
    

    
<snip>
    

    
[libx264 @ 0x1b8c9c0] frame I:7     Avg QP:13.71  size:152207
    
[libx264 @ 0x1b8c9c0] frame P:190   Avg QP:16.66  size: 50949
    
[libx264 @ 0x1b8c9c0] mb I  I16..4: 27.1% 30.8% 42.1%
    
[libx264 @ 0x1b8c9c0] mb P  I16..4:  6.8%  6.0%  0.8%  P16..4: 61.8%  0.0%  0.0%  0.0%  0.0%    skip:24.7%
    
[libx264 @ 0x1b8c9c0] 8x8 transform intra:41.2% inter:86.9%
    
[libx264 @ 0x1b8c9c0] coded y,uvDC,uvAC intra: 92.2% 28.3% 5.4% inter: 50.3% 1.9% 0.0%
    
[libx264 @ 0x1b8c9c0] i16 v,h,dc,p:  7%  7% 77%  8%
    
[libx264 @ 0x1b8c9c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 15% 49%  6%  4%  3%  5%  3%  8%
    
[libx264 @ 0x1b8c9c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 25% 24%  6%  7%  4%  6%  3%  6%
    
[libx264 @ 0x1b8c9c0] i8c dc,h,v,p: 72% 14% 10%  4%
    
[libx264 @ 0x1b8c9c0] Weighted P-Frames: Y:0.0% UV:0.0%
    
[libx264 @ 0x1b8c9c0] kb/s:6539.11
    
</snip></snip>

    ffmpeg, on the other hand, produces the following output that is almost identical but includes B-frames :

    [libx264 @ 0x20b9c40] using mv_range_thread = 56
    
[libx264 @ 0x20b9c40] using SAR=1/1
    
[libx264 @ 0x20b9c40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
    
[libx264 @ 0x20b9c40] profile High, level 3.1
    
[h264 @ 0x20b8160] detected 4 logical cores
    
Output #0, h264, to './out.264':
    
  Metadata:
    
    encoder         : Lavf54.63.104
    
    Stream #0:0, 0, 1/90000: Video: h264, yuvj420p, 1280x720 [SAR 1:1 DAR 16:9], 1001/15000, q=-1--1, 90k tbn, 14.99 tbc
    
Stream mapping:
    
  Stream #0:0 -> #0:0 (h264 -> libx264)
    

    
<snip>
    

    
[libx264 @ 0x20b9c40] frame=   0 QP=17.22 NAL=3 Slice:I Poc:0   I:3600 P:0    SKIP:0    size=122835 bytes
    
[libx264 @ 0x20b9c40] frame=   1 QP=18.75 NAL=2 Slice:P Poc:8   I:984  P:2045 SKIP:571  size=54208 bytes
    
[libx264 @ 0x20b9c40] frame=   2 QP=19.40 NAL=2 Slice:B Poc:4   I:447  P:1581 SKIP:1572 size=24930 bytes
    
[libx264 @ 0x20b9c40] frame=   3 QP=19.78 NAL=0 Slice:B Poc:2   I:199  P:1002 SKIP:2399 size=10717 bytes
    
[libx264 @ 0x20b9c40] frame=   4 QP=20.19 NAL=0 Slice:B Poc:6   I:204  P:1155 SKIP:2241 size=15937 bytes
    
[libx264 @ 0x20b9c40] frame=   5 QP=18.11 NAL=2 Slice:P Poc:16  I:990  P:2221 SKIP:389  size=64240 bytes
    
[libx264 @ 0x20b9c40] frame=   6 QP=19.35 NAL=2 Slice:B Poc:12  I:439  P:1784 SKIP:1377 size=34048 bytes
    
[libx264 @ 0x20b9c40] frame=   7 QP=19.88 NAL=0 Slice:B Poc:10  I:275  P:1035 SKIP:2290 size=16911 bytes
    
[libx264 @ 0x20b9c40] frame=   8 QP=19.91 NAL=0 Slice:B Poc:14  I:257  P:1270 SKIP:2073 size=19172 bytes
    
[libx264 @ 0x20b9c40] frame=   9 QP=17.90 NAL=2 Slice:P Poc:24  I:962  P:2204 SKIP:434  size=67439 bytes
    
[libx264 @ 0x20b9c40] frame=  10 QP=18.84 NAL=2 Slice:B Poc:20  I:474  P:1911 SKIP:1215 size=37742 bytes
    

    
<snip>
    

    
[libx264 @ 0x20b9c40] frame I:7     Avg QP:15.95  size:130124
    
[libx264 @ 0x20b9c40] frame P:52    Avg QP:17.78  size: 64787
    
[libx264 @ 0x20b9c40] frame B:138   Avg QP:19.32  size: 26231
    
[libx264 @ 0x20b9c40] consecutive B-frames:  6.6%  0.0%  0.0% 93.4%
    
[libx264 @ 0x20b9c40] mb I  I16..4: 30.2% 35.2% 34.6%
    
[libx264 @ 0x20b9c40] mb P  I16..4: 13.9% 11.4%  0.3%  P16..4: 60.4%  0.0%  0.0%  0.0%  0.0%    skip:13.9%
    
[libx264 @ 0x20b9c40] mb B  I16..4:  5.7%  3.3%  0.0%  B16..8: 15.8%  0.0%  0.0%  direct:25.7%  skip:49.5%  L0:43.2% L1:37.3% BI:19.5%
    
[libx264 @ 0x20b9c40] 8x8 transform intra:39.4% inter:77.2%
    
[libx264 @ 0x20b9c40] coded y,uvDC,uvAC intra: 90.7% 26.6% 3.0% inter: 34.0% 4.1% 0.0%
    
[libx264 @ 0x20b9c40] i16 v,h,dc,p:  7%  7% 77%  9%
    
[libx264 @ 0x20b9c40] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 16% 51%  5%  4%  3%  5%  3%  7%
    
[libx264 @ 0x20b9c40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 27% 20%  6%  6%  3%  6%  3%  6%
    
[libx264 @ 0x20b9c40] i8c dc,h,v,p: 71% 15% 11%  3%
    
[libx264 @ 0x20b9c40] Weighted P-Frames: Y:0.0% UV:0.0%
    
[libx264 @ 0x20b9c40] kb/s:4807.16
    
</snip></snip>

    I’m sure I’m missing something simple, but I can’t for the life of me see what it is. Any assistance would be greatly appreciated.

  • libavcodec/libx264 do not produce B-frames

    6 novembre 2013, par Rob Schmidt

    I am writing an application in C++ that uses libavcodec with libx264 to encode video. However, the encoded data ended up being much larger than I expected. I analyzed the results and discovered that my encoding never produced B-frames, only I- and P-frames.

    I created a standalone utility based on the ffmpeg source code and examples to test my encoder setup. It reads in an H.264 file, re-encodes the decoded frames, and outputs the result to a file using the ITU H.264 Annex B format. I also used ffmpeg to perform the same operation so I could compare against a known good implementation. My utility never outputs B-frames whereas ffmpeg does.

    I have since tried to figure out what ffmpeg does that my code doesn't. I first tried manually specifying encoder settings related to B-frames. This had no effect.

    I then tried running both ffmpeg and my utility under gdb and comparing the contents of the AVStream, AVCodecContext, and X264Context prior to opening the encoder and manually setting any fields that appeared different. Even with identical settings, I still only produce I- and P-frames.

    Finally, I thought that perhaps the problem was with my timestamp handling. I reworked my test utility to mimic the pipeline used by ffmpeg and to output timestamp debugging output like ffmpeg does. Even with my timestamps identical to ffmpeg's I still get no B-frames.

    At this point I don't know what else to try. When I run ffmpeg, I run it with the command line below. Note that aside from the "superfast" preset, I pretty much use the default values.

    ffmpeg -v debug -i ~/annexb.264 -codec:v libx264 -preset superfast -g 30 -f h264 ./out.264

    The code that configures the encoder is listed below. It specifies the "superfast" preset too.

    static AVStream *add_video_stream(AVFormatContext *output_ctx, AVCodec **output_codec, enum AVCodecID codec_id)
    
{
    
    *output_codec = avcodec_find_encoder(codec_id);
    
    if (*output_codec == NULL) {
    
        printf("Could not find encoder for &#39;%s&#39; (%d)\n", avcodec_get_name(codec_id), codec_id);
    
        return NULL;
    
    }
    

    
    AVStream *output_stream = avformat_new_stream(output_ctx, *output_codec);
    
    if (output_stream == NULL) {
    
        printf("Could not create video stream.\n");
    
        return NULL;
    
    }
    
    output_stream->id = output_ctx->nb_streams - 1;
    
    AVCodecContext *codec_ctx = output_stream->codec;
    

    
    avcodec_get_context_defaults3(codec_ctx, *output_codec);
    

    
    codec_ctx->width = 1280;
    
    codec_ctx->height = 720;
    

    
    codec_ctx->time_base.den = 15000;
    
    codec_ctx->time_base.num = 1001;
    

    
/*    codec_ctx->gop_size = 30;*/
    
    codec_ctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
    

    
    // try to force B-frame output
    
/*    codec_ctx->max_b_frames = 3;*/
    
/*    codec_ctx->b_frame_strategy = 2;*/
    

    
    output_stream->sample_aspect_ratio.num = 1;
    
    output_stream->sample_aspect_ratio.den = 1;
    

    
    codec_ctx->sample_aspect_ratio.num = 1;
    
    codec_ctx->sample_aspect_ratio.den = 1;
    

    
    codec_ctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
    

    
    codec_ctx->bits_per_raw_sample = 8;
    

    
    if ((output_ctx->oformat->flags &amp; AVFMT_GLOBALHEADER) != 0) {
    
        codec_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
    
    }
    

    
    return output_stream;
    
}
    

    

    
int main(int argc, char **argv)
    
{
    
    // ... open input file 
    

    
    avformat_alloc_output_context2(&amp;output_ctx, NULL, "h264", output_path);
    
    if (output_ctx == NULL) {
    
        fprintf(stderr, "Unable to allocate output context.\n");
    
        return 1;
    
    } 
    

    
    AVCodec *output_codec = NULL;
    
    output_stream = add_video_stream(output_ctx, &amp;output_codec, output_ctx->oformat->video_codec);
    
    if (output_stream == NULL) {
    
        fprintf(stderr, "Error adding video stream to output context.\n");
    
        return 1;
    
    }
    
    encode_ctx = output_stream->codec;
    

    
    // seems to have no effect
    
#if 0
    
    if (decode_ctx->extradata_size != 0) {
    
        size_t extradata_size = decode_ctx->extradata_size;
    
        printf("extradata_size: %zu\n", extradata_size);
    
        encode_ctx->extradata = av_mallocz(extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
    
        memcpy(encode_ctx->extradata, decode_ctx->extradata, extradata_size);
    
        encode_ctx->extradata_size = extradata_size;
    
    }
    
#endif // 0
    

    
    AVDictionary *opts = NULL;
    
    av_dict_set(&amp;opts, "preset", "superfast", 0);
    
    // av_dict_set(&amp;opts, "threads", "auto", 0); // seems to have no effect
    

    
    ret = avcodec_open2(encode_ctx, output_codec, &amp;opts);
    
    if (ret &lt; 0) {
    
        fprintf(stderr, "Unable to open output video cocec: %s\n", av_err2str(ret));
    
        return 1;
    
    }
    

    
    // ... decoding/encoding loop, clean up, etc.
    

    
    return 0;
    
}

    My test utility produces the following debug output in which you can see there are no B-frames produced :

    [libx264 @ 0x1b8c9c0] using mv_range_thread = 56
    
[libx264 @ 0x1b8c9c0] using SAR=1/1
    
[libx264 @ 0x1b8c9c0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
    
[libx264 @ 0x1b8c9c0] profile High, level 3.1
    
Output #0, h264, to &#39;./out.264&#39;:
    
    Stream #0:0, 0, 1/90000: Video: h264, yuvj420p, 1280x720 [SAR 1:1 DAR 16:9], 1001/15000, q=-1--1, 90k tbn, 14.99 tbc
    

    
<snip>
    

    
[libx264 @ 0x1b8c9c0] frame=   0 QP=17.22 NAL=3 Slice:I Poc:0   I:3600 P:0    SKIP:0    size=122837 bytes
    
[libx264 @ 0x1b8c9c0] frame=   1 QP=18.03 NAL=2 Slice:P Poc:2   I:411  P:1825 SKIP:1364 size=25863 bytes
    
[libx264 @ 0x1b8c9c0] frame=   2 QP=17.03 NAL=2 Slice:P Poc:4   I:369  P:2159 SKIP:1072 size=37880 bytes
    
[libx264 @ 0x1b8c9c0] frame=   3 QP=16.90 NAL=2 Slice:P Poc:6   I:498  P:2330 SKIP:772  size=50509 bytes
    
[libx264 @ 0x1b8c9c0] frame=   4 QP=16.68 NAL=2 Slice:P Poc:8   I:504  P:2233 SKIP:863  size=50791 bytes
    
[libx264 @ 0x1b8c9c0] frame=   5 QP=16.52 NAL=2 Slice:P Poc:10  I:513  P:2286 SKIP:801  size=51820 bytes
    
[libx264 @ 0x1b8c9c0] frame=   6 QP=16.49 NAL=2 Slice:P Poc:12  I:461  P:2293 SKIP:846  size=51311 bytes
    
[libx264 @ 0x1b8c9c0] frame=   7 QP=16.65 NAL=2 Slice:P Poc:14  I:476  P:2287 SKIP:837  size=51196 bytes
    
[libx264 @ 0x1b8c9c0] frame=   8 QP=16.66 NAL=2 Slice:P Poc:16  I:508  P:2240 SKIP:852  size=51577 bytes
    
[libx264 @ 0x1b8c9c0] frame=   9 QP=16.55 NAL=2 Slice:P Poc:18  I:477  P:2278 SKIP:845  size=51531 bytes
    
[libx264 @ 0x1b8c9c0] frame=  10 QP=16.67 NAL=2 Slice:P Poc:20  I:517  P:2233 SKIP:850  size=51946 bytes
    

    
<snip>
    

    
[libx264 @ 0x1b8c9c0] frame I:7     Avg QP:13.71  size:152207
    
[libx264 @ 0x1b8c9c0] frame P:190   Avg QP:16.66  size: 50949
    
[libx264 @ 0x1b8c9c0] mb I  I16..4: 27.1% 30.8% 42.1%
    
[libx264 @ 0x1b8c9c0] mb P  I16..4:  6.8%  6.0%  0.8%  P16..4: 61.8%  0.0%  0.0%  0.0%  0.0%    skip:24.7%
    
[libx264 @ 0x1b8c9c0] 8x8 transform intra:41.2% inter:86.9%
    
[libx264 @ 0x1b8c9c0] coded y,uvDC,uvAC intra: 92.2% 28.3% 5.4% inter: 50.3% 1.9% 0.0%
    
[libx264 @ 0x1b8c9c0] i16 v,h,dc,p:  7%  7% 77%  8%
    
[libx264 @ 0x1b8c9c0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 15% 49%  6%  4%  3%  5%  3%  8%
    
[libx264 @ 0x1b8c9c0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 19% 25% 24%  6%  7%  4%  6%  3%  6%
    
[libx264 @ 0x1b8c9c0] i8c dc,h,v,p: 72% 14% 10%  4%
    
[libx264 @ 0x1b8c9c0] Weighted P-Frames: Y:0.0% UV:0.0%
    
[libx264 @ 0x1b8c9c0] kb/s:6539.11
    
</snip></snip>

    ffmpeg, on the other hand, produces the following output that is almost identical but includes B-frames :

    [libx264 @ 0x20b9c40] using mv_range_thread = 56
    
[libx264 @ 0x20b9c40] using SAR=1/1
    
[libx264 @ 0x20b9c40] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
    
[libx264 @ 0x20b9c40] profile High, level 3.1
    
[h264 @ 0x20b8160] detected 4 logical cores
    
Output #0, h264, to &#39;./out.264&#39;:
    
  Metadata:
    
    encoder         : Lavf54.63.104
    
    Stream #0:0, 0, 1/90000: Video: h264, yuvj420p, 1280x720 [SAR 1:1 DAR 16:9], 1001/15000, q=-1--1, 90k tbn, 14.99 tbc
    
Stream mapping:
    
  Stream #0:0 -> #0:0 (h264 -> libx264)
    

    
<snip>
    

    
[libx264 @ 0x20b9c40] frame=   0 QP=17.22 NAL=3 Slice:I Poc:0   I:3600 P:0    SKIP:0    size=122835 bytes
    
[libx264 @ 0x20b9c40] frame=   1 QP=18.75 NAL=2 Slice:P Poc:8   I:984  P:2045 SKIP:571  size=54208 bytes
    
[libx264 @ 0x20b9c40] frame=   2 QP=19.40 NAL=2 Slice:B Poc:4   I:447  P:1581 SKIP:1572 size=24930 bytes
    
[libx264 @ 0x20b9c40] frame=   3 QP=19.78 NAL=0 Slice:B Poc:2   I:199  P:1002 SKIP:2399 size=10717 bytes
    
[libx264 @ 0x20b9c40] frame=   4 QP=20.19 NAL=0 Slice:B Poc:6   I:204  P:1155 SKIP:2241 size=15937 bytes
    
[libx264 @ 0x20b9c40] frame=   5 QP=18.11 NAL=2 Slice:P Poc:16  I:990  P:2221 SKIP:389  size=64240 bytes
    
[libx264 @ 0x20b9c40] frame=   6 QP=19.35 NAL=2 Slice:B Poc:12  I:439  P:1784 SKIP:1377 size=34048 bytes
    
[libx264 @ 0x20b9c40] frame=   7 QP=19.88 NAL=0 Slice:B Poc:10  I:275  P:1035 SKIP:2290 size=16911 bytes
    
[libx264 @ 0x20b9c40] frame=   8 QP=19.91 NAL=0 Slice:B Poc:14  I:257  P:1270 SKIP:2073 size=19172 bytes
    
[libx264 @ 0x20b9c40] frame=   9 QP=17.90 NAL=2 Slice:P Poc:24  I:962  P:2204 SKIP:434  size=67439 bytes
    
[libx264 @ 0x20b9c40] frame=  10 QP=18.84 NAL=2 Slice:B Poc:20  I:474  P:1911 SKIP:1215 size=37742 bytes
    

    
<snip>
    

    
[libx264 @ 0x20b9c40] frame I:7     Avg QP:15.95  size:130124
    
[libx264 @ 0x20b9c40] frame P:52    Avg QP:17.78  size: 64787
    
[libx264 @ 0x20b9c40] frame B:138   Avg QP:19.32  size: 26231
    
[libx264 @ 0x20b9c40] consecutive B-frames:  6.6%  0.0%  0.0% 93.4%
    
[libx264 @ 0x20b9c40] mb I  I16..4: 30.2% 35.2% 34.6%
    
[libx264 @ 0x20b9c40] mb P  I16..4: 13.9% 11.4%  0.3%  P16..4: 60.4%  0.0%  0.0%  0.0%  0.0%    skip:13.9%
    
[libx264 @ 0x20b9c40] mb B  I16..4:  5.7%  3.3%  0.0%  B16..8: 15.8%  0.0%  0.0%  direct:25.7%  skip:49.5%  L0:43.2% L1:37.3% BI:19.5%
    
[libx264 @ 0x20b9c40] 8x8 transform intra:39.4% inter:77.2%
    
[libx264 @ 0x20b9c40] coded y,uvDC,uvAC intra: 90.7% 26.6% 3.0% inter: 34.0% 4.1% 0.0%
    
[libx264 @ 0x20b9c40] i16 v,h,dc,p:  7%  7% 77%  9%
    
[libx264 @ 0x20b9c40] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  7% 16% 51%  5%  4%  3%  5%  3%  7%
    
[libx264 @ 0x20b9c40] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 22% 27% 20%  6%  6%  3%  6%  3%  6%
    
[libx264 @ 0x20b9c40] i8c dc,h,v,p: 71% 15% 11%  3%
    
[libx264 @ 0x20b9c40] Weighted P-Frames: Y:0.0% UV:0.0%
    
[libx264 @ 0x20b9c40] kb/s:4807.16
    
</snip></snip>

    I'm sure I'm missing something simple, but I can't for the life of me see what it is. Any assistance would be greatly appreciated.

  • Convert video to animated GIF with FFmpeg [migrated]

    5 janvier 2014, par flexage

    I have FFmpeg installed and working on my Ubuntu 12.04 LTS Server.

    I have managed to successfully automate the process of uploading a video and converting it to both H264/MP4 and OGV for display on the web.

    I also wanted to generate an animated GIF thumbnail for the video.

    I have got as far as the following, which I'm pretty sure is generating 2 frames a second for the first 10 seconds of the video :

    /usr/local/bin/ffmpeg -i "$3/uploads/video-queue/$1.$2" -vf scale=320:-1 -t 10 -r 2 "$3/uploads/video-queue/processing/$1.gif"

    What I would prefer to do is generate 1 frame every 25 seconds for the duration of the entire video, but also with a maximum number of frames set as something like 50 frames.

    I would prefer not to have dependencies on other components such as Image Magik, and I would like to keep this purely shell based.

    Thanks in advance ! You guys are way smarter than me for sure !

    Here is the complete console output from an ffmpeg run of the command above :

    root@ubuntu:/home/fckster/etc/php5# /home/fckster/public_html/cronscripts/process-video-gif.sh 1-1388841621 wmv /home/fckster/public_html
    
ffmpeg version N-59480-g8feaa83-syslint Copyright (c) 2000-2014 the FFmpeg developers
    
  built on Jan  2 2014 00:32:20 with gcc 4.6 (Ubuntu/Linaro 4.6.3-1ubuntu5)
    
  configuration: --prefix=/usr/local/cpffmpeg --enable-shared --enable-nonfree --enable-gpl --enable-pthreads --enable-libopencore-amrnb --enable-decoder=liba52 --enable-libopencore-amrwb --enable-libfaac --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-libxvid --extra-cflags=-I/usr/local/cpffmpeg/include/ --extra-ldflags=-L/usr/local/cpffmpeg/lib --enable-version3 --extra-version=syslint
    
  libavutil      52. 59.100 / 52. 59.100
    
  libavcodec     55. 47.100 / 55. 47.100
    
  libavformat    55. 22.102 / 55. 22.102
    
  libavdevice    55.  5.102 / 55.  5.102
    
  libavfilter     4.  0.103 /  4.  0.103
    
  libswscale      2.  5.101 /  2.  5.101
    
  libswresample   0. 17.104 /  0. 17.104
    
  libpostproc    52.  3.100 / 52.  3.100
    
[wmv3 @ 0x24dd680] Extra data: 8 bits left, value: 0
    
Guessed Channel Layout for  Input Stream #0.1 : stereo
    
Input #0, asf, from &#39;/home/fckster/public_html/uploads/video-queue/1-1388841621.wmv&#39;:
    
  Metadata:
    
    WM/ToolName     : Flip4Mac WMV Export Component for QuickTime (Mac)
    
    WM/ToolVersion  : 2204
    
    encoder         : Lavf54.29.104
    
  Duration: 00:01:11.30, start: 0.140000, bitrate: 2096 kb/s
    
    Stream #0:0: Video: wmv3 (Main) (WMV3 / 0x33564D57), yuv420p, 1280x720, 29.97 tbr, 1k tbn, 1k tbc
    
    Stream #0:1: Audio: wmav2 (a[1][0][0] / 0x0161), 44100 Hz, stereo, fltp, 48 kb/s
    
[wmv3 @ 0x24dd680] Extra data: 8 bits left, value: 0
    
Output #0, gif, to &#39;/home/fckster/public_html/uploads/video-queue/processing/1-1388841621.gif&#39;:
    
  Metadata:
    
    WM/ToolName     : Flip4Mac WMV Export Component for QuickTime (Mac)
    
    WM/ToolVersion  : 2204
    
    encoder         : Lavf55.22.102
    
    Stream #0:0: Video: gif, pal8, 320x180, q=2-31, 200 kb/s, 100 tbn, 10 tbc
    
Stream mapping:
    
  Stream #0:0 -> #0:0 (wmv3 -> gif)
    
Press [q] to stop, [?] for help
    
frame=   87 fps= 52 q=0.0 Lsize=    2131kB time=00:00:10.00 bitrate=1745.9kbits/s dup=0 drop=170    
    
video:2219kB audio:0kB subtitle:0 global headers:0kB muxing overhead -3.939009%

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