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• FFMPEG and libx264, WMP and QT playback at different res/aspect than specified

  10 septembre 2013, par Foltz

  So, for a little context. I'm trying to convert a JPEG2000 in .mxf video to an h264 in .mp4, maintaining its resolution/frame-size/aspect ratio. I'll say up front I'm not 100% sure on how all these ratios tie together.

  So, my input file is 720x486. I have a sample h264 file with specs I'm trying to emulate (from an OpenCube video ingest machine) with ffmpeg. The OpenCube file plays back at 720x486 in both Quick Time 7 and Windows Media Player 12. It reports a PAR of 9:10 and DAR of 4:3 (Using VideoSpec to see these values).

  When I make my derivative h264 using ffmpeg I can run the command :

  ffmpeg -i lac-test.mxf -vcodec libx264 -s 720x486 -aspect 4:3 -b:v 2500000 -pix_fmt yuv420p -coder 0 -acodec libfaac -b:a 256000 lac-test.mp4

  The output file reports the correct values in VideoSpec (720x486, DAR 4:3, PAR 9:10), but plays back in QT at 648x486. Weirder, the video plays back at the proper resolution (that is, same size as the sample OpenCube file).

  Now, an alternative command creates yet another predicament :

  ffmpeg -i lac-test.mxf -vcodec libx264 -s 720x486 -b:v 2500000 -pix_fmt yuv420p -coder 0 -acodec libfaac -b:a 256000 lac-test.mp4

  So omitting the aspect ratio gives me an output file that plays at 720x486 in QT7 (good !) but reports a DAR of 1.481 and an Undefine PAR. Unfortunately, THIS file plays back slightly too wide in WMP12.

  I've tried a slew of different strings to try and get something that plays back correctly. I've tried using various filters with the -fv flag such as :

  ffmpeg -i lac-test.mxf -vcodec libx264 -vf "scale=720x486,setsar=9:10,setdar=4:3" -b:v 2500000 -pix_fmt yuv420p -coder 0 -acodec libfaac -b:a 256000 lac-test.mp4

  This results in a video that shows all the correct specs in VideoSpec, and plays back correctly in WMP12 (same size as OpenCube file), but still plays back at 648x486 in QT7.

  What gives ?

• FFmpeg fontcolor_expr to dynamically change fontcolor over time

  26 juin 2017, par Matthew

  I’m using Fluent-FFmpeg with Node.JS to create videos with text overlaid on them and I’m wanting to change the color of the text as the video progresses.

  My filters follow this pattern :

  drawtext=enable='between(t,18.93,20.28)':fontfile=fonts/cousine-bold.ttf:fontsize=144:fontcolor_expr=%{expr\\\: if(between(t\\, 0\\, 20)\\, 888888\\, 111111)}:x=82:y=288:text='PROGRAMMING'

  And it prints out this stuff :

  ffmpeg version 3.3.2 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with Apple LLVM version 8.1.0 (clang-802.0.42)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libfreetype --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  
    libavutil      55. 58.100 / 55. 58.100
  
    libavcodec     57. 89.100 / 57. 89.100
  
    libavformat    57. 71.100 / 57. 71.100
  
    libavdevice    57.  6.100 / 57.  6.100
  
    libavfilter     6. 82.100 /  6. 82.100
  
    libavresample   3.  5.  0 /  3.  5.  0
  
    libswscale      4.  6.100 /  4.  6.100
  
    libswresample   2.  7.100 /  2.  7.100
  
    libpostproc    54.  5.100 / 54.  5.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'uploads/0c719e39820366bc62c8fd66a6327828':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2017-06-23T00:19:46.000000Z
  
      com.apple.quicktime.make: Apple
  
      com.apple.quicktime.model: MacBookPro9,2
  
      com.apple.quicktime.software: Mac OS X 10.12.5 (16F73)
  
      com.apple.quicktime.creationdate: 2017-06-22T17:18:42-0700
  
    Duration: 00:00:22.00, start: 0.000000, bitrate: 3408 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 3091 kb/s, 15 fps, 15 tbr, 30k tbn, 50 tbc (default)
  
      Metadata:
  
        creation_time   : 2017-06-23T00:19:46.000000Z
  
        handler_name    : Core Media Data Handler
  
        encoder         : H.264
  
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 316 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-06-23T00:19:46.000000Z
  
        handler_name    : Core Media Data Handler
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  
    Stream #0:1 -> #0:1 (aac (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  [libx264 @ 0x7ff72e810a00] using SAR=1/1
  
  [libx264 @ 0x7ff72e810a00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
  
  [libx264 @ 0x7ff72e810a00] profile High, level 3.1
  
  [libx264 @ 0x7ff72e810a00] 264 - core 148 r2748 97eaef2 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=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 chroma_qp_offset=-2 threads=6 lookahead_threads=1 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=250 keyint_min=15 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
  
  Output #0, mp4, to './outputFile.mp4':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      com.apple.quicktime.creationdate: 2017-06-22T17:18:42-0700
  
      com.apple.quicktime.make: Apple
  
      com.apple.quicktime.model: MacBookPro9,2
  
      com.apple.quicktime.software: Mac OS X 10.12.5 (16F73)
  
      encoder         : Lavf57.71.100
  
      Stream #0:0(und): Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 15 fps, 15360 tbn, 15 tbc (default)
  
      Metadata:
  
        creation_time   : 2017-06-23T00:19:46.000000Z
  
        handler_name    : Core Media Data Handler
  
        encoder         : Lavc57.89.100 libx264
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
      Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s (default)
  
      Metadata:
  
        creation_time   : 2017-06-23T00:19:46.000000Z
  
        handler_name    : Core Media Data Handler
  
        encoder         : Lavc57.89.100 aac
  
  frame=   52 fps=0.0 q=27.0 size=      37kB time=00:00:04.66 bitrate=  65.7kbits/s speed=8.74x    
  
  frame=   72 fps= 70 q=27.0 size=     187kB time=00:00:06.03 bitrate= 253.4kbits/s speed=5.83x    
  
  frame=   95 fps= 61 q=27.0 size=     358kB time=00:00:07.52 bitrate= 390.4kbits/s speed=4.82x    
  
  frame=  117 fps= 57 q=27.0 size=     569kB time=00:00:08.98 bitrate= 518.9kbits/s speed=4.35x    
  
  frame=  137 fps= 53 q=27.0 size=     732kB time=00:00:10.32 bitrate= 580.2kbits/s speed=4.03x    
  
  frame=  159 fps= 52 q=27.0 size=     942kB time=00:00:11.79 bitrate= 654.7kbits/s speed=3.84x    
  
  frame=  180 fps= 50 q=27.0 size=    1110kB time=00:00:13.18 bitrate= 689.5kbits/s speed=3.67x    
  
  frame=  204 fps= 50 q=27.0 size=    1331kB time=00:00:14.78 bitrate= 737.2kbits/s speed= 3.6x    
  
  frame=  223 fps= 48 q=27.0 size=    1486kB time=00:00:16.06 bitrate= 757.9kbits/s speed=3.49x    
  
  frame=  248 fps= 48 q=27.0 size=    1708kB time=00:00:17.71 bitrate= 789.7kbits/s speed=3.46x    
  
  frame=  266 fps= 47 q=27.0 size=    1859kB time=00:00:18.92 bitrate= 805.0kbits/s speed=3.35x    
  
  frame=  285 fps= 46 q=27.0 size=    2013kB time=00:00:20.19 bitrate= 816.4kbits/s speed=3.28x    
  
  [drawtext @ 0x7ff72d84bc00] Cannot find color '888888.000000'
  
      Last message repeated 9 times
  
  frame=  308 fps= 46 q=27.0 size=    2224kB time=00:00:21.75 bitrate= 837.5kbits/s speed=3.27x    
  
  frame=  330 fps= 46 q=27.0 size=    2401kB time=00:00:21.96 bitrate= 895.5kbits/s speed=3.06x    
  
  frame=  330 fps= 41 q=-1.0 Lsize=    2834kB time=00:00:22.00 bitrate=1055.0kbits/s speed=2.73x    
  
  video:2484kB audio:338kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.441003%
  
  [libx264 @ 0x7ff72e810a00] frame I:22    Avg QP:13.64  size: 47604
  
  [libx264 @ 0x7ff72e810a00] frame P:154   Avg QP:16.76  size:  8574
  
  [libx264 @ 0x7ff72e810a00] frame B:154   Avg QP:19.42  size:  1138
  
  [libx264 @ 0x7ff72e810a00] consecutive B-frames:  6.7% 93.3%  0.0%  0.0%
  
  [libx264 @ 0x7ff72e810a00] mb I  I16..4: 85.1% 13.3%  1.6%
  
  [libx264 @ 0x7ff72e810a00] mb P  I16..4:  5.5%  3.1%  0.0%  P16..4: 41.5%  4.0%  5.5%  0.0%  0.0%    skip:40.4%
  
  [libx264 @ 0x7ff72e810a00] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8: 14.7%  0.1%  0.0%  direct: 4.7%  skip:80.4%  L0:28.0% L1:71.4% BI: 0.7%
  
  [libx264 @ 0x7ff72e810a00] 8x8 transform intra:21.7% inter:84.8%
  
  [libx264 @ 0x7ff72e810a00] coded y,uvDC,uvAC intra: 60.5% 98.6% 92.9% inter: 6.0% 24.3% 3.1%
  
  [libx264 @ 0x7ff72e810a00] i16 v,h,dc,p: 35% 19% 43%  3%
  
  [libx264 @ 0x7ff72e810a00] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 10%  7% 80%  1%  1%  1%  1%  0%  0%
  
  [libx264 @ 0x7ff72e810a00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 20% 45%  0%  0%  0%  0%  0%  0%
  
  [libx264 @ 0x7ff72e810a00] i8c dc,h,v,p: 77%  9% 10%  4%
  
  [libx264 @ 0x7ff72e810a00] Weighted P-Frames: Y:0.0% UV:0.0%
  
  [libx264 @ 0x7ff72e810a00] ref P L0: 75.3%  0.3% 17.1%  7.3%
  
  [libx264 @ 0x7ff72e810a00] ref B L0: 80.0% 20.0%
  
  [libx264 @ 0x7ff72e810a00] kb/s:924.66
  
  [aac @ 0x7ff72e812200] Qavg: 2159.960

  In particular this annoying bit :

  [drawtext @ 0x7ff72d84bc00] Cannot find color '888888.000000'

  However, it would be really nice to do something like this :

  fontcolor_expr=%{expr\\\\: if(between(t\\, 0\\, 20)\\, pink\\, white)}

  Which prints out this error :

  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  frame=  287 fps= 46 q=27.0 size=    2023kB time=00:00:20.31 bitrate= 815.9kbits/s speed=3.27x    
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Undefined constant or missing '(' in 'pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] [Eval @ 0x7fff5f7760c0] Missing ')' or too many args in 'if(between(t,0,20),pink,white)'
  
  [Parsed_drawtext_0 @ 0x7ff3cf523300] Expression 'if(between(t, 0, 20), pink, white)' for the expr text expansion function is not valid

  There aren’t a lot of examples of fontcolor_expr, so I wanted to see if anyone had experience with this. Any tips on changing fonrcolors dynamically without creating multiple filters ?

  Please note that fontcolor_expr=white and fontcolor_expr=888888 are valid and create videos with a fixed font color.

• Scale filter crashes with error when used from transcoding example

  27 juin 2017, par Vali

  I’ve modified a bit (just to compile in c++) this code example :
  https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/transcoding.c.

  What works : as is (null filter), a number of other filters like framerate, drawtext, ...

  What doesn’t work : scale filter when scaling down.

  I use the following syntax for scale ( I’ve tried many others also, same effect) :
  "scale=w=iw/2 :-1"

  The error is : "Input picture width (240) is greater than stride (128)" where the values for width and stride depend on the input.

  Misc environment info : windows, VS 2017, input example : rtsp ://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov

  Any clue as to what I’m doing wrong ?

  Thanks !

  ---

  EDITED to add working code sample

  ---

  #pragma comment(lib, "avcodec.lib")
  
  #pragma comment(lib, "avutil.lib")
  
  #pragma comment(lib, "avformat.lib")
  
  #pragma comment(lib, "avfilter.lib")
  
  
  
  /*
  
  * Copyright (c) 2010 Nicolas George
  
  * Copyright (c) 2011 Stefano Sabatini
  
  * Copyright (c) 2014 Andrey Utkin
  
  *
  
  **** EDITED 2017 for testing (see original here: https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/transcoding.c)
  
  *
  
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  
  * of this software and associated documentation files (the "Software"), to deal
  
  * in the Software without restriction, including without limitation the rights
  
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  
  * copies of the Software, and to permit persons to whom the Software is
  
  * furnished to do so, subject to the following conditions:
  
  *
  
  * The above copyright notice and this permission notice shall be included in
  
  * all copies or substantial portions of the Software.
  
  *
  
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  
  * THE SOFTWARE.
  
  */
  
  
  
  /**
  
  * @file
  
  * API example for demuxing, decoding, filtering, encoding and muxing
  
  * @example transcoding.c
  
  */
  
  
  
  extern "C"
  
  {
  
      #include <libavcodec></libavcodec>avcodec.h>
  
      #include <libavformat></libavformat>avformat.h>
  
      #include <libavfilter></libavfilter>avfiltergraph.h>
  
      #include <libavfilter></libavfilter>buffersink.h>
  
      #include <libavfilter></libavfilter>buffersrc.h>
  
      #include <libavutil></libavutil>opt.h>
  
      #include <libavutil></libavutil>pixdesc.h>
  
  }
  
  
  
  
  
  static AVFormatContext *ifmt_ctx;
  
  static AVFormatContext *ofmt_ctx;
  
  typedef struct FilteringContext {
  
      AVFilterContext *buffersink_ctx;
  
      AVFilterContext *buffersrc_ctx;
  
      AVFilterGraph *filter_graph;
  
  } FilteringContext;
  
  static FilteringContext *filter_ctx;
  
  
  
  typedef struct StreamContext {
  
      AVCodecContext *dec_ctx;
  
      AVCodecContext *enc_ctx;
  
  } StreamContext;
  
  static StreamContext *stream_ctx;
  
  
  
  static int open_input_file(const char *filename, int&amp; videoStreamIndex)
  
  {
  
      int ret;
  
      unsigned int i;
  
  
  
      ifmt_ctx = NULL;
  
      if ((ret = avformat_open_input(&amp;ifmt_ctx, filename, NULL, NULL)) &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
  
          return ret;
  
      }
  
  
  
      if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
  
          return ret;
  
      }
  
  
  
      // Just need video
  
      videoStreamIndex = -1;
  
      for (unsigned int i = 0; i &lt; ifmt_ctx->nb_streams; i++)
  
      {
  
          if (ifmt_ctx->streams[i]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO)
  
              continue;
  
          videoStreamIndex = i;
  
          break;
  
      }
  
      if (videoStreamIndex &lt; 0)
  
      {
  
          av_log(NULL, AV_LOG_ERROR, "Cannot find video stream\n");
  
          return videoStreamIndex;
  
      }
  
  
  
  
  
      stream_ctx = (StreamContext*)av_mallocz_array(ifmt_ctx->nb_streams, sizeof(*stream_ctx));
  
      if (!stream_ctx)
  
          return AVERROR(ENOMEM);
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
  
  
          // Just need video
  
          if (i != videoStreamIndex)
  
              continue;
  
  
  
  
  
          AVStream *stream = ifmt_ctx->streams[i];
  
          AVCodec *dec = avcodec_find_decoder(stream->codecpar->codec_id);
  
          AVCodecContext *codec_ctx;
  
          if (!dec) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed to find decoder for stream #%u\n", i);
  
              return AVERROR_DECODER_NOT_FOUND;
  
          }
  
          codec_ctx = avcodec_alloc_context3(dec);
  
          if (!codec_ctx) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed to allocate the decoder context for stream #%u\n", i);
  
              return AVERROR(ENOMEM);
  
          }
  
          ret = avcodec_parameters_to_context(codec_ctx, stream->codecpar);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed to copy decoder parameters to input decoder context "
  
                  "for stream #%u\n", i);
  
              return ret;
  
          }
  
          /* Reencode video &amp; audio and remux subtitles etc. */
  
          if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO
  
              || codec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
              if (codec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
  
                  codec_ctx->framerate = av_guess_frame_rate(ifmt_ctx, stream, NULL);
  
              /* Open decoder */
  
              ret = avcodec_open2(codec_ctx, dec, NULL);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Failed to open decoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
          }
  
          stream_ctx[i].dec_ctx = codec_ctx;
  
      }
  
  
  
      av_dump_format(ifmt_ctx, 0, filename, 0);
  
      return 0;
  
  }
  
  
  
  static int open_output_file(const char *filename, const int videoStreamIndex)
  
  {
  
      AVStream *out_stream;
  
      AVStream *in_stream;
  
      AVCodecContext *dec_ctx, *enc_ctx;
  
      AVCodec *encoder;
  
      int ret;
  
      unsigned int i;
  
  
  
      ofmt_ctx = NULL;
  
      avformat_alloc_output_context2(&amp;ofmt_ctx, NULL, NULL, filename);
  
      if (!ofmt_ctx) {
  
          av_log(NULL, AV_LOG_ERROR, "Could not create output context\n");
  
          return AVERROR_UNKNOWN;
  
      }
  
  
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          // Just need video
  
          if (i != videoStreamIndex)
  
              continue;
  
  
  
          out_stream = avformat_new_stream(ofmt_ctx, NULL);
  
          if (!out_stream) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n");
  
              return AVERROR_UNKNOWN;
  
          }
  
  
  
          in_stream = ifmt_ctx->streams[i];
  
          dec_ctx = stream_ctx[i].dec_ctx;
  
  
  
          if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
  
              /* in this example, we choose transcoding to same codec */
  
              encoder = avcodec_find_encoder(dec_ctx->codec_id);
  
              if (!encoder) {
  
                  av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
  
                  return AVERROR_INVALIDDATA;
  
              }
  
              enc_ctx = avcodec_alloc_context3(encoder);
  
              if (!enc_ctx) {
  
                  av_log(NULL, AV_LOG_FATAL, "Failed to allocate the encoder context\n");
  
                  return AVERROR(ENOMEM);
  
              }
  
  
  
              /* In this example, we transcode to same properties (picture size,
  
              * sample rate etc.). These properties can be changed for output
  
              * streams easily using filters */
  
              enc_ctx->height = dec_ctx->height;
  
              enc_ctx->width = dec_ctx->width;
  
              enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
  
              /* take first format from list of supported formats */
  
              if (encoder->pix_fmts)
  
                  enc_ctx->pix_fmt = encoder->pix_fmts[0];
  
              else
  
                  enc_ctx->pix_fmt = dec_ctx->pix_fmt;
  
  
  
              /* video time_base can be set to whatever is handy and supported by encoder */
  
              //enc_ctx->time_base = av_inv_q(dec_ctx->framerate);
  
              enc_ctx->time_base = dec_ctx->time_base;
  
  
  
  
  
              /* Third parameter can be used to pass settings to encoder */
  
              ret = avcodec_open2(enc_ctx, encoder, NULL);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
              ret = avcodec_parameters_from_context(out_stream->codecpar, enc_ctx);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Failed to copy encoder parameters to output stream #%u\n", i);
  
                  return ret;
  
              }
  
              if (ofmt_ctx->oformat->flags &amp; AVFMT_GLOBALHEADER)
  
                  enc_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
  
  
              out_stream->time_base = enc_ctx->time_base;
  
              stream_ctx[i].enc_ctx = enc_ctx;
  
          }
  
          else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) {
  
              av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i);
  
              return AVERROR_INVALIDDATA;
  
          }
  
          else {
  
              /* if this stream must be remuxed */
  
              ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
  
              if (ret &lt; 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Copying parameters for stream #%u failed\n", i);
  
                  return ret;
  
              }
  
              out_stream->time_base = in_stream->time_base;
  
          }
  
  
  
      }
  
      av_dump_format(ofmt_ctx, 0, filename, 1);
  
  
  
      if (!(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE)) {
  
          ret = avio_open(&amp;ofmt_ctx->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Could not open output file '%s'", filename);
  
              return ret;
  
          }
  
      }
  
  
  
      /* init muxer, write output file header */
  
      ret = avformat_write_header(ofmt_ctx, NULL);
  
      if (ret &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n");
  
          return ret;
  
      }
  
  
  
      return 0;
  
  }
  
  
  
  static int init_filter(FilteringContext* fctx, AVCodecContext *dec_ctx,
  
      AVCodecContext *enc_ctx, const char *filter_spec)
  
  {
  
      char args[512];
  
      int ret = 0;
  
      AVFilter *buffersrc = NULL;
  
      AVFilter *buffersink = NULL;
  
      AVFilterContext *buffersrc_ctx = NULL;
  
      AVFilterContext *buffersink_ctx = NULL;
  
      AVFilterInOut *outputs = avfilter_inout_alloc();
  
      AVFilterInOut *inputs = avfilter_inout_alloc();
  
      AVFilterGraph *filter_graph = avfilter_graph_alloc();
  
  
  
      if (!outputs || !inputs || !filter_graph) {
  
          ret = AVERROR(ENOMEM);
  
          goto end;
  
      }
  
  
  
      if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
  
          buffersrc = avfilter_get_by_name("buffer");
  
          buffersink = avfilter_get_by_name("buffersink");
  
          if (!buffersrc || !buffersink) {
  
              av_log(NULL, AV_LOG_ERROR, "filtering source or sink element not found\n");
  
              ret = AVERROR_UNKNOWN;
  
              goto end;
  
          }
  
  
  
          snprintf(args, sizeof(args),
  
              "video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
  
              dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt,
  
              dec_ctx->time_base.num, dec_ctx->time_base.den,
  
              dec_ctx->sample_aspect_ratio.num,
  
              dec_ctx->sample_aspect_ratio.den);
  
  
  
          ret = avfilter_graph_create_filter(&amp;buffersrc_ctx, buffersrc, "in",
  
              args, NULL, filter_graph);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot create buffer source\n");
  
              goto end;
  
          }
  
  
  
          ret = avfilter_graph_create_filter(&amp;buffersink_ctx, buffersink, "out",
  
              NULL, NULL, filter_graph);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot create buffer sink\n");
  
              goto end;
  
          }
  
  
  
          ret = av_opt_set_bin(buffersink_ctx, "pix_fmts",
  
              (uint8_t*)&amp;enc_ctx->pix_fmt, sizeof(enc_ctx->pix_fmt),
  
              AV_OPT_SEARCH_CHILDREN);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Cannot set output pixel format\n");
  
              goto end;
  
          }
  
      }
  
      else {
  
          ret = AVERROR_UNKNOWN;
  
          goto end;
  
      }
  
  
  
      /* Endpoints for the filter graph. */
  
      outputs->name = av_strdup("in");
  
      outputs->filter_ctx = buffersrc_ctx;
  
      outputs->pad_idx = 0;
  
      outputs->next = NULL;
  
  
  
      inputs->name = av_strdup("out");
  
      inputs->filter_ctx = buffersink_ctx;
  
      inputs->pad_idx = 0;
  
      inputs->next = NULL;
  
  
  
      if (!outputs->name || !inputs->name) {
  
          ret = AVERROR(ENOMEM);
  
          goto end;
  
      }
  
  
  
      if ((ret = avfilter_graph_parse_ptr(filter_graph, filter_spec,
  
          &amp;inputs, &amp;outputs, NULL)) &lt; 0)
  
          goto end;
  
  
  
      if ((ret = avfilter_graph_config(filter_graph, NULL)) &lt; 0)
  
          goto end;
  
  
  
      /* Fill FilteringContext */
  
      fctx->buffersrc_ctx = buffersrc_ctx;
  
      fctx->buffersink_ctx = buffersink_ctx;
  
      fctx->filter_graph = filter_graph;
  
  
  
  end:
  
      avfilter_inout_free(&amp;inputs);
  
      avfilter_inout_free(&amp;outputs);
  
  
  
      return ret;
  
  }
  
  
  
  static int init_filters(const int videoStreamIndex)
  
  {
  
      const char *filter_spec;
  
      unsigned int i;
  
      int ret;
  
      filter_ctx = (FilteringContext*)av_malloc_array(ifmt_ctx->nb_streams, sizeof(*filter_ctx));
  
      if (!filter_ctx)
  
          return AVERROR(ENOMEM);
  
  
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
  
  
          // Just video
  
          if (i != videoStreamIndex)
  
              continue;
  
  
  
          filter_ctx[i].buffersrc_ctx = NULL;
  
          filter_ctx[i].buffersink_ctx = NULL;
  
          filter_ctx[i].filter_graph = NULL;
  
          if (!(ifmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO
  
              || ifmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO))
  
              continue;
  
  
  
          filter_spec = "null"; /* passthrough (dummy) filter for video */
  
          //filter_spec = "scale=w=iw/2:-1";
  
          // filter_spec = "drawtext=fontfile=FreeSerif.ttf: text='%{localtime}': x=w-text_w: y=0: fontsize=24: fontcolor=yellow@1.0: box=1: boxcolor=red@1.0";
  
          // filter_spec = "drawtext=fontfile=FreeSerif.ttf :text='test': x=w-text_w: y=text_h: fontsize=24: fontcolor=yellow@1.0: box=1: boxcolor=red@1.0";
  
  
  
          ret = init_filter(&amp;filter_ctx[i], stream_ctx[i].dec_ctx,
  
              stream_ctx[i].enc_ctx, filter_spec);
  
          if (ret)
  
              return ret;
  
      }
  
      return 0;
  
  }
  
  
  
  static int encode_write_frame(AVFrame *filt_frame, unsigned int stream_index, int *got_frame, const int videoStreamIndex) {
  
  
  
      // Just video
  
      if (stream_index != videoStreamIndex)
  
          return 0;
  
  
  
      int ret;
  
      int got_frame_local;
  
      AVPacket enc_pkt;
  
      int(*enc_func)(AVCodecContext *, AVPacket *, const AVFrame *, int *) =
  
          (ifmt_ctx->streams[stream_index]->codecpar->codec_type ==
  
              AVMEDIA_TYPE_VIDEO) ? avcodec_encode_video2 : avcodec_encode_audio2;
  
  
  
      if (!got_frame)
  
          got_frame = &amp;got_frame_local;
  
  
  
      // av_log(NULL, AV_LOG_INFO, "Encoding frame\n");
  
      /* encode filtered frame */
  
      enc_pkt.data = NULL;
  
      enc_pkt.size = 0;
  
      av_init_packet(&amp;enc_pkt);
  
  
  
      ret = enc_func(stream_ctx[stream_index].enc_ctx, &amp;enc_pkt,
  
          filt_frame, got_frame);
  
  
  
      av_frame_free(&amp;filt_frame);
  
      if (ret &lt; 0)
  
          return ret;
  
      if (!(*got_frame))
  
          return 0;
  
  
  
      /* prepare packet for muxing */
  
      /*enc_pkt.stream_index = stream_index;
  
      av_packet_rescale_ts(&amp;enc_pkt, stream_ctx[stream_index].enc_ctx->time_base, ofmt_ctx->streams[stream_index]->time_base);*/
  
      enc_pkt.stream_index = 0;
  
      av_packet_rescale_ts(&amp;enc_pkt, stream_ctx[stream_index].enc_ctx->time_base, ofmt_ctx->streams[0]->time_base);
  
  
  
      av_log(NULL, AV_LOG_DEBUG, "Muxing frame\n");
  
      /* mux encoded frame */
  
      ret = av_interleaved_write_frame(ofmt_ctx, &amp;enc_pkt);
  
      return ret;
  
  }
  
  
  
  static int filter_encode_write_frame(AVFrame *frame, unsigned int stream_index, const int videoStreamIndex)
  
  {
  
      // Just video, all else crashes
  
      if (stream_index != videoStreamIndex)
  
          return 0;
  
  
  
      int ret;
  
      AVFrame *filt_frame;
  
  
  
      // av_log(NULL, AV_LOG_INFO, "Pushing decoded frame to filters\n");
  
      /* push the decoded frame into the filtergraph */
  
      ret = av_buffersrc_add_frame_flags(filter_ctx[stream_index].buffersrc_ctx,
  
          frame, 0);
  
      if (ret &lt; 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Error while feeding the filtergraph\n");
  
          return ret;
  
      }
  
  
  
      /* pull filtered frames from the filtergraph */
  
      while (1) {
  
          filt_frame = av_frame_alloc();
  
          if (!filt_frame) {
  
              ret = AVERROR(ENOMEM);
  
              break;
  
          }
  
          // av_log(NULL, AV_LOG_INFO, "Pulling filtered frame from filters\n");
  
          ret = av_buffersink_get_frame(filter_ctx[stream_index].buffersink_ctx,
  
              filt_frame);
  
          if (ret &lt; 0) {
  
              /* if no more frames for output - returns AVERROR(EAGAIN)
  
              * if flushed and no more frames for output - returns AVERROR_EOF
  
              * rewrite retcode to 0 to show it as normal procedure completion
  
              */
  
              if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
  
                  ret = 0;
  
              av_frame_free(&amp;filt_frame);
  
              break;
  
          }
  
  
  
          filt_frame->pict_type = AV_PICTURE_TYPE_NONE;
  
          ret = encode_write_frame(filt_frame, stream_index, NULL, videoStreamIndex);
  
          if (ret &lt; 0)
  
              break;
  
      }
  
  
  
      return ret;
  
  }
  
  
  
  static int flush_encoder(unsigned int stream_index, const int videoStreamIndex)
  
  {
  
      int ret;
  
      int got_frame;
  
  
  
      // Just video
  
      if (stream_index != videoStreamIndex)
  
          return 0;
  
  
  
      if (!(stream_ctx[stream_index].enc_ctx->codec->capabilities &amp;
  
          AV_CODEC_CAP_DELAY))
  
          return 0;
  
  
  
      while (1) {
  
          av_log(NULL, AV_LOG_INFO, "Flushing stream #%u encoder\n", stream_index);
  
          ret = encode_write_frame(NULL, stream_index, &amp;got_frame, videoStreamIndex);
  
          if (ret &lt; 0)
  
              break;
  
          if (!got_frame)
  
              return 0;
  
      }
  
      return ret;
  
  }
  
  
  
  
  
  #include <vector>
  
  
  
  int main(int argc, char **argv)
  
  {
  
      int ret;
  
  
  
      AVPacket packet;
  
      packet.data = NULL;
  
      packet.size = 0;
  
  
  
      AVFrame *frame = NULL;
  
      enum AVMediaType type;
  
      unsigned int stream_index;
  
      unsigned int i;
  
      int got_frame;
  
      int(*dec_func)(AVCodecContext *, AVFrame *, int *, const AVPacket *);
  
  
  
  
  
  #ifdef _DEBUG
  
      // Hardcoded arguments
  
      std::vector varguments;
  
      {
  
          varguments.push_back(argv[0]);
  
  
  
          // Source
  
          varguments.push_back("./big_buck_bunny_short.mp4 ");
  
  
  
          // Destination
  
          varguments.push_back("./big_buck_bunny_short-processed.mp4");
  
      }
  
  
  
      char** arguments = new char*[varguments.size()];
  
      for (unsigned int i = 0; i &lt; varguments.size(); i++)
  
      {
  
          arguments[i] = varguments[i];
  
      }
  
      argc = varguments.size();
  
      argv = arguments;
  
  #endif // _DEBUG
  
  
  
  
  
      if (argc != 3) {
  
          av_log(NULL, AV_LOG_ERROR, "Usage: %s <input file="file" /> <output file="file">\n", argv[0]);
  
          return 1;
  
      }
  
  
  
      av_register_all();
  
      avfilter_register_all();
  
  
  
      int videoStreamIndex = -1;
  
      if ((ret = open_input_file(argv[1], videoStreamIndex)) &lt; 0)
  
          goto end;
  
      if ((ret = open_output_file(argv[2], videoStreamIndex)) &lt; 0)
  
          goto end;
  
      if ((ret = init_filters(videoStreamIndex)) &lt; 0)
  
          goto end;
  
  
  
      // Stop after a couple of frames
  
      int framesToGet = 100;
  
  
  
      /* read all packets */
  
      //while (framesToGet--)
  
      while(1)
  
      {
  
          if ((ret = av_read_frame(ifmt_ctx, &amp;packet)) &lt; 0)
  
              break;
  
          stream_index = packet.stream_index;
  
  
  
          // I just need video
  
          if (stream_index != videoStreamIndex) {
  
              av_packet_unref(&amp;packet);
  
              continue;
  
          }
  
  
  
          type = ifmt_ctx->streams[packet.stream_index]->codecpar->codec_type;
  
          av_log(NULL, AV_LOG_DEBUG, "Demuxer gave frame of stream_index %u\n",
  
              stream_index);
  
  
  
          if (filter_ctx[stream_index].filter_graph) {
  
              av_log(NULL, AV_LOG_DEBUG, "Going to reencode&amp;filter the frame\n");
  
              frame = av_frame_alloc();
  
              if (!frame) {
  
                  ret = AVERROR(ENOMEM);
  
                  break;
  
              }
  
              av_packet_rescale_ts(&amp;packet,
  
                  ifmt_ctx->streams[stream_index]->time_base,
  
                  stream_ctx[stream_index].dec_ctx->time_base);
  
              dec_func = (type == AVMEDIA_TYPE_VIDEO) ? avcodec_decode_video2 :
  
                  avcodec_decode_audio4;
  
              ret = dec_func(stream_ctx[stream_index].dec_ctx, frame,
  
                  &amp;got_frame, &amp;packet);
  
              if (ret &lt; 0) {
  
                  av_frame_free(&amp;frame);
  
                  av_log(NULL, AV_LOG_ERROR, "Decoding failed\n");
  
                  break;
  
              }
  
  
  
              if (got_frame) {
  
                  frame->pts = frame->best_effort_timestamp;
  
                  ret = filter_encode_write_frame(frame, stream_index, videoStreamIndex);
  
                  av_frame_free(&amp;frame);
  
                  if (ret &lt; 0)
  
                      goto end;
  
              }
  
              else {
  
                  av_frame_free(&amp;frame);
  
              }
  
          }
  
          else {
  
              /* remux this frame without reencoding */
  
              av_packet_rescale_ts(&amp;packet,
  
                  ifmt_ctx->streams[stream_index]->time_base,
  
                  ofmt_ctx->streams[stream_index]->time_base);
  
  
  
              ret = av_interleaved_write_frame(ofmt_ctx, &amp;packet);
  
              if (ret &lt; 0)
  
                  goto end;
  
          }
  
          av_packet_unref(&amp;packet);
  
      }
  
  
  
      /* flush filters and encoders */
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          /* flush filter */
  
          if (!filter_ctx[i].filter_graph)
  
              continue;
  
          ret = filter_encode_write_frame(NULL, i, videoStreamIndex);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Flushing filter failed\n");
  
              goto end;
  
          }
  
  
  
          /* flush encoder */
  
          ret = flush_encoder(i, videoStreamIndex);
  
          if (ret &lt; 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Flushing encoder failed\n");
  
              goto end;
  
          }
  
      }
  
  
  
      av_write_trailer(ofmt_ctx);
  
  end:
  
      av_packet_unref(&amp;packet);
  
      av_frame_free(&amp;frame);
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          // Just video
  
          if (i != videoStreamIndex)
  
              continue;
  
          avcodec_free_context(&amp;stream_ctx[i].dec_ctx);
  
          if (ofmt_ctx &amp;&amp; ofmt_ctx->nb_streams > i &amp;&amp; ofmt_ctx->streams[i] &amp;&amp; stream_ctx[i].enc_ctx)
  
              avcodec_free_context(&amp;stream_ctx[i].enc_ctx);
  
          if (filter_ctx &amp;&amp; filter_ctx[i].filter_graph)
  
              avfilter_graph_free(&amp;filter_ctx[i].filter_graph);
  
      }
  
      av_free(filter_ctx);
  
      av_free(stream_ctx);
  
      avformat_close_input(&amp;ifmt_ctx);
  
      if (ofmt_ctx &amp;&amp; !(ofmt_ctx->oformat->flags &amp; AVFMT_NOFILE))
  
          avio_closep(&amp;ofmt_ctx->pb);
  
      avformat_free_context(ofmt_ctx);
  
  
  
      /*if (ret &lt; 0)
  
          av_log(NULL, AV_LOG_ERROR, "Error occurred: %s\n", av_err2str(ret));*/
  
  
  
      return ret ? 1 : 0;
  
  }
  
  </output></vector>