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• Concat videos with ffmpeg does not work [migrated]

  6 mai 2013, par Yannick Schinko

  I'm currently trying to concat 3 Videos which don't have a audio stream and adding a audio file in the same step.

  I created this command which should do the work :

  ffmpeg -y -r 30 -i data\intro.mp4 -vcodec ppm -f image2pipe -i data\render.ppm -i data\outro.mp4 -i "data\I could be the one.mp3" -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a copy -filter_complex "[0:0] [1:0] [2:0] concat=n=3:v=1:a=0 [v]" -map [v] -map 3:0 -shortest -metadata title="Development of BrainStoneMod" -metadata description="This is the development of the BrainStoneMod starting from 08th April, 2013" -metadata author="The_BrainStone" -metadata copyright="2013" -metadata year="2013" -metadata composer="" -metadata TBPM="" -metadata TDAT="" gource.mp4

  It is indeed a long command but it satisfied my needs until I wanted to embend the actual video in between a intro and a outro.

  I'm getting this log :

  ffmpeg version N-51639-g7775992 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Apr  5 2013 22:24:22 with gcc 4.8.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
  
  isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libcaca --enable-libfreetyp
  
  e --enable-libgsm --enable-libilbc --enable-libmp3lame --enable-libopencore-amrn
  
  b --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libr
  
  tmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheo
  
  ra --enable-libtwolame --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li
  
  bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --ena
  
  ble-zlib
  
    libavutil      52. 25.100 / 52. 25.100
  
    libavcodec     55.  2.100 / 55.  2.100
  
    libavformat    55.  1.100 / 55.  1.100
  
    libavdevice    55.  0.100 / 55.  0.100
  
    libavfilter     3. 49.100 /  3. 49.100
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  2.100 / 52.  2.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'data\intro.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf55.1.100
  
    Duration: 00:00:04.00, start: 0.000000, bitrate: 42 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720
  
  [SAR 1:1 DAR 16:9], 38 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  
      Metadata:
  
        handler_name    : VideoHandler
  
  [image2pipe @ 027f0a80] Stream #0: not enough frames to estimate rate; consider
  
  increasing probesize
  
  Input #1, image2pipe, from 'data\render.ppm':
  
    Duration: N/A, bitrate: N/A
  
      Stream #1:0: Video: ppm, rgb24, 1280x720, 25 tbr, 25 tbn, 25 tbc
  
  Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'data\outro.mp4':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf55.1.100
  
    Duration: 00:00:04.00, start: 0.000000, bitrate: 42 kb/s
  
      Stream #2:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720
  
  [SAR 1:1 DAR 16:9], 38 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
  
      Metadata:
  
        handler_name    : VideoHandler
  
  [mp3 @ 02757020] max_analyze_duration 5000000 reached at 5015510 microseconds
  
  [mp3 @ 02757020] Estimating duration from bitrate, this may be inaccurate
  
  Input #3, mp3, from 'data\I could be the one.mp3':
  
    Metadata:
  
      TBPM            : 140
  
      TDAT            : 0000
  
      composer        : Kevin Als
  
    Duration: 00:03:55.91, start: 0.000000, bitrate: 320 kb/s
  
      Stream #3:0: Audio: mp3, 44100 Hz, stereo, s16p, 320 kb/s
  
  [Parsed_concat_0 @ 028b20e0] Input link in1:v0 parameters (size 1280x720, SAR 0:
  
  1) do not match the corresponding output link in0:v0 parameters (1280x720, SAR 1
  
  :1)
  
  [Parsed_concat_0 @ 028b20e0] Failed to configure output pad on Parsed_concat_0

  What should I do ?

  By the way : This is the command I used before and worked out great :

  ffmpeg -y -r 30 -i "data\I could be the one.mp3" -vcodec ppm -f image2pipe -i data\render.ppm -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a copy -map 1:0 -map 0:0 -shortest -metadata title="Development of BrainStoneMod" -metadata description="This is the development of the BrainStoneMod starting from 08th April, 2013" -metadata author="The_BrainStone" -metadata copyright="2013" -metadata year="2013" -metadata composer="" -metadata TBPM="" -metadata TDAT="" gource.mp4

  Any ideas ?

• compiling errors with ffmpeg on linux [closed]

  7 mai 2013, par David Tree

  Hi all ,I downloaded the latest ffmpeg source code and successfully installed it on Ubuntu

  But I failed to compile a simple demo.
  This was created with QtCreator with the .pro file as follows :

  QT -= gui

  TARGET = qt_v4l2
  TEMPLATE = app
  SOURCES += \
  ../tutorial01.c

  LIBS += -L/-lavcodec -lavformat -lswscale -lavutil

  Here are the error messages ,just to name a few :

  ../tutorial01.c:22:16 : error : unknown type name 'AVFrame'

  ../tutorial01.c:55:5 : error : unknown type name 'uint8_t'

  ../tutorial01.c:68:50 : error : 'NULL' undeclared (first use in this function)

  /tutorial01.c:84:22 : error : request for member 'streams' in something not a structure or union

  ../tutorial01.c:84:57 : error : 'AVMEDIA_TYPE_VIDEO' undeclared (first use in this function)

  ../tutorial01.c:122:24 : error : expected expression before ')' token

  ../tutorial01.c:128:21 : error : 'AVPicture' undeclared (first use in this function)
  ../tutorial01.c:128:32 : error : expected expression before ')' token

  .

  And this is the ffmpeg installed
  ffmpeg version 1.1.git Copyright (c) 2000-2013 the FFmpeg developers
  built on May 7 2013 14:10:58 with gcc 4.7 (Ubuntu/Linaro 4.7.2-2ubuntu1)
  configuration : —enable-gpl —prefix=/usr —enable-libx264 —enable-pthreads

  And this is the actuall CODE

  https://github.com/phamquy/FFmpeg-tutorial-samples/blob/master/tutorial01.c

• Does H.264 encoded video with BT.709 matrix include any gamma adjustment ?

  27 janvier 2019, par MoDJ

  I have read the BT.709 spec a number of times and the thing that is just not clear is should an encoded H.264 bitstream actually apply any gamma curve to the encoded data ? Note the specific mention of a gamma like formula in the BT.709 spec. Apple provided examples of OpenGL or Metal shaders that read YUV data from CoreVideo provided buffers do not do any sort of gamma adjustment. YUV values are being read and processed as though they are simple linear values. I also examined the source code of ffmpeg and found no gamma adjustments being applied after the BT.709 scaling step. I then created a test video with just two linear grayscale colors 5 and 26 corresponding to 2% and 10% levels. When converted to H.264 with both ffmpeg and iMovie, the output BT.709 values are (YCbCr) (20 128 128) and (38 128 128) and these values exactly match the output of the BT.709 conversion matrix without any gamma adjustment.

  A great piece of background on this topic can be found at Quicktime Gamma Bug. It seems that some historical issues with Quicktime and Adobe encoders were improperly doing different gamma adjustments and the results made video streams look awful on different players. This is really confusing because if you compare to sRGB, it clearly indicates how to apply a gamma encoding and then decode it to convert between sRGB and linear. Why does BT.709 go into so much detail about the same sort of gamma adjustment curve if no gamma adjustment is applied after the matrix step when creating a h.264 data stream ? Are all the color steps in a h.264 stream meant to be coded as straight linear (gamma 1.0) values ?

  In case specific example input would make things more clear, I am attaching 3 color bar images, the exact values of different colors can be displayed in an image editor with these image files.

  This first image is in the sRGB colorspace and is tagged as sRGB.

  

  This second image has been converted to the linear RGB colorspace and is tagged with a linear RGB profile.

  

  This third image has been converted to REC.709 profile levels with Rec709-elle-V4-rec709.icc from elles_icc_profiles
  . This seems to be what one would need to do to simulate "camera" gamma as described in BT.709.

  

  Note how the sRGB value in the lower right corner (0x555555) becomes linear RGB (0x171717) and the BT.709 gamma encoded value becomes (0x464646). What is unclear is if I should be passing a linear RGB value into ffmpeg or if I should be passing an already BT.709 gamma encoded value which would then need to be decoded in the client before the linear conversion Matrix step to get back to RGB.

  Update :

  Based on the feedback, I have updated my C based implementation and Metal shader and uploaded to github as an iOS example project MetalBT709Decoder.

  Encoding a normalized linear RGB value is implemented like this :

  static inline
  
  int BT709_convertLinearRGBToYCbCr(
  
                              float Rn,
  
                              float Gn,
  
                              float Bn,
  
                              int *YPtr,
  
                              int *CbPtr,
  
                              int *CrPtr,
  
                              int applyGammaMap)
  
  {
  
    // Gamma adjustment to non-linear value
  
  
  
    if (applyGammaMap) {
  
      Rn = BT709_linearNormToNonLinear(Rn);
  
      Gn = BT709_linearNormToNonLinear(Gn);
  
      Bn = BT709_linearNormToNonLinear(Bn);
  
    }
  
  
  
    // https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.709-6-201506-I!!PDF-E.pdf
  
  
  
    float Ey = (Kr * Rn) + (Kg * Gn) + (Kb * Bn);
  
    float Eb = (Bn - Ey) / Eb_minus_Ey_Range;
  
    float Er = (Rn - Ey) / Er_minus_Ey_Range;
  
  
  
    // Quant Y to range [16, 235] (inclusive 219 values)
  
    // Quant Eb, Er to range [16, 240] (inclusive 224 values, centered at 128)
  
  
  
    float AdjEy = (Ey * (YMax-YMin)) + 16;
  
    float AdjEb = (Eb * (UVMax-UVMin)) + 128;
  
    float AdjEr = (Er * (UVMax-UVMin)) + 128;
  
  
  
    *YPtr = (int) round(AdjEy);
  
    *CbPtr = (int) round(AdjEb);
  
    *CrPtr = (int) round(AdjEr);
  
  
  
    return 0;
  
  }

  Decoding from YCbCr to linear RGB is implemented like so :

  static inline
  
  int BT709_convertYCbCrToLinearRGB(
  
                               int Y,
  
                               int Cb,
  
                               int Cr,
  
                               float *RPtr,
  
                               float *GPtr,
  
                               float *BPtr,
  
                               int applyGammaMap)
  
  {
  
    // https://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.709_conversion
  
    // http://www.niwa.nu/2013/05/understanding-yuv-values/
  
  
  
    // Normalize Y to range [0 255]
  
    //
  
    // Note that the matrix multiply will adjust
  
    // this byte normalized range to account for
  
    // the limited range [16 235]
  
  
  
    float Yn = (Y - 16) * (1.0f / 255.0f);
  
  
  
    // Normalize Cb and CR with zero at 128 and range [0 255]
  
    // Note that matrix will adjust to limited range [16 240]
  
  
  
    float Cbn = (Cb - 128) * (1.0f / 255.0f);
  
    float Crn = (Cr - 128) * (1.0f / 255.0f);
  
  
  
    const float YScale = 255.0f / (YMax-YMin);
  
    const float UVScale = 255.0f / (UVMax-UVMin);
  
  
  
    const
  
    float BT709Mat[] = {
  
      YScale,   0.000f,  (UVScale * Er_minus_Ey_Range),
  
      YScale, (-1.0f * UVScale * Eb_minus_Ey_Range * Kb_over_Kg),  (-1.0f * UVScale * Er_minus_Ey_Range * Kr_over_Kg),
  
      YScale, (UVScale * Eb_minus_Ey_Range),  0.000f,
  
    };
  
  
  
    // Matrix multiply operation
  
    //
  
    // rgb = BT709Mat * YCbCr
  
  
  
    // Convert input Y, Cb, Cr to normalized float values
  
  
  
    float Rn = (Yn * BT709Mat[0]) + (Cbn * BT709Mat[1]) + (Crn * BT709Mat[2]);
  
    float Gn = (Yn * BT709Mat[3]) + (Cbn * BT709Mat[4]) + (Crn * BT709Mat[5]);
  
    float Bn = (Yn * BT709Mat[6]) + (Cbn * BT709Mat[7]) + (Crn * BT709Mat[8]);
  
  
  
    // Saturate normalzied linear (R G B) to range [0.0, 1.0]
  
  
  
    Rn = saturatef(Rn);
  
    Gn = saturatef(Gn);
  
    Bn = saturatef(Bn);
  
  
  
    // Gamma adjustment for RGB components after matrix transform
  
  
  
    if (applyGammaMap) {
  
      Rn = BT709_nonLinearNormToLinear(Rn);
  
      Gn = BT709_nonLinearNormToLinear(Gn);
  
      Bn = BT709_nonLinearNormToLinear(Bn);
  
    }
  
  
  
    *RPtr = Rn;
  
    *GPtr = Gn;
  
    *BPtr = Bn;
  
  
  
    return 0;
  
  }

  I believe this logic is implemented correctly, but I am having a very difficult time validating the results. When I generate a .m4v file that contains gamma adjusted color values (osxcolor_test_image_24bit_BT709.m4v), the result come out as expected. But a test case like (bars_709_Frame01.m4v) that I found here does not seem to work as the color bar values seem to be encoded as linear (no gamma adjustment).

  For a SMPTE test pattern, the 0.75 graylevel is linear RGB (191 191 191), should this RGB be encoded with no gamma adjustment as (Y Cb Cr) (180 128 128) or should the value in the bitstream appear as the gamma adjusted (Y Cb Cr) (206 128 128) ?

  (follow up)
  After doing additional research into this gamma issue, it has become clear that what Apple is actually doing in AVFoundation is using a 1.961 gamma function. This is the case when encoding with AVAssetWriterInputPixelBufferAdaptor, when using vImage, or with CoreVideo APIs. This piecewise gamma function is defined as follows :

  #define APPLE_GAMMA_196 (1.960938f)
  
  
  
  static inline
  
  float Apple196_nonLinearNormToLinear(float normV) {
  
    const float xIntercept = 0.05583828f;
  
  
  
    if (normV < xIntercept) {
  
      normV *= (1.0f / 16.0f);
  
    } else {
  
      const float gamma = APPLE_GAMMA_196;
  
      normV = pow(normV, gamma);
  
    }
  
  
  
    return normV;
  
  }
  
  
  
  static inline
  
  float Apple196_linearNormToNonLinear(float normV) {
  
    const float yIntercept = 0.00349f;
  
  
  
    if (normV < yIntercept) {
  
      normV *= 16.0f;
  
    } else {
  
      const float gamma = 1.0f / APPLE_GAMMA_196;
  
      normV = pow(normV, gamma);
  
    }
  
  
  
    return normV;
  
  }