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• Fix some typos in the documentation.

  8 janvier 2013, par Tim Terriberry

  Fix some typos in the documentation.
  git-svn-id : http://svn.xiph.org/trunk/theora@18759 0101bb08-14d6-0310-b084-bc0e0c8e3800
  

  • [DH] include/theora/codec.h

• Error when trying to convert mp3 with image to mp4 using ffmpeg

  25 octobre 2012, par Ello

  The mp3 has an image in it, maybe some album images. When I use ffmpeg to convert it to mp4, it goes wrong. But if I convert an mp3 without an image, it succeeds.

  My command is like this :

  ffmpeg -i input.mp3 output.mp4

  Here's the error :

  Stream mapping:
  
    Stream #0:1 -> #0:0 (mjpeg -> mpeg4)
  
    Stream #0:0 -> #0:1 (mp3 -> aac)
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

  Here is all the console output :

  ellodeiMac:mine ello$ ffmpeg -frames 0 -i 4.mp3 -y test.mp4
  
  ffmpeg version 0.11.2 Copyright (c) 2000-2012 the FFmpeg developers
  
    built on Oct 24 2012 12:21:13 with llvm_gcc 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00)
  
    configuration: --disable-yasm
  
    libavutil      51. 54.100 / 51. 54.100
  
    libavcodec     54. 23.100 / 54. 23.100
  
    libavformat    54.  6.100 / 54.  6.100
  
    libavdevice    54.  0.100 / 54.  0.100
  
    libavfilter     2. 77.100 /  2. 77.100
  
    libswscale      2.  1.100 /  2.  1.100
  
    libswresample   0. 15.100 /  0. 15.100
  
  [mp3 @ 0x7fa12301ae00] max_analyze_duration 5000000 reached at 5015510
  
  Input #0, mp3, from '4.mp3':
  
    Metadata:
  
      artist          : 贵族乐团
  
      album           : 美声天籁
  
      title           : 肖邦离别曲
  
      Tagging time    : 2012-09-18T08:12:10
  
    Duration: 00:04:01.44, start: 0.000000, bitrate: 129 kb/s
  
      Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
  
      Stream #0:1: Video: mjpeg, yuvj420p, 240x240 [SAR 1:1 DAR 1:1], 90k tbr, 90k tbn, 90k tbc
  
      Metadata:
  
        title           : e
  
        comment         : Cover (front)
  
  [buffer @ 0x109115780] w:240 h:240 pixfmt:yuvj420p tb:1/90000 sar:1/1 sws_param:flags=2
  
  [buffersink @ 0x109133720] No opaque field provided
  
  [format @ 0x1091338e0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'format'
  
  [scale @ 0x109133bc0] w:240 h:240 fmt:yuvj420p sar:1/1 -> w:240 h:240 fmt:yuv420p sar:1/1 flags:0x4
  
  [mp4 @ 0x7fa123035c00] Frame rate very high for a muxer not efficiently supporting it.
  
  Please consider specifying a lower framerate, a different muxer or -vsync 2
  
  [aformat @ 0x109136ec0] auto-inserting filter 'auto-inserted resampler 0' between the filter 'src' and the filter 'aformat'
  
  [aresample @ 0x1091370c0] chl:stereo fmt:s16 r:44100Hz -> chl:stereo fmt:flt r:44100Hz
  
  [mpeg4 @ 0x7fa12303be00] timebase 1/90000 not supported by MPEG 4 standard, the maximum 
  
  admitted value for the timebase denominator is 65535
  
  Output #0, mp4, to 'test.mp4':
  
    Metadata:
  
      artist          : 贵族乐团
  
      album           : 美声天籁
  
      title           : 肖邦离别曲
  
      Tagging time    : 2012-09-18T08:12:10
  
      Stream #0:0: Video: mpeg4, yuv420p, 240x240 [SAR 1:1 DAR 1:1], q=2-31, 200 kb/s, 90k tbn, 90k tbc
  
      Metadata:
  
        title           : e
  
        comment         : Cover (front)
  
      Stream #0:1: Audio: none, 44100 Hz, stereo, flt, 128 kb/s
  
  Stream mapping:
  
    Stream #0:1 -> #0:0 (mjpeg -> mpeg4)
  
    Stream #0:0 -> #0:1 (mp3 -> aac)
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

• libavcodec get video duration and framerate

  17 septembre 2013, par Tishu

  I have a video encoded in .3gp h.264 and I am looking to get its framerate and duration in C. Here is the code I use after opening the file and finding the appropriate codecs :

  AVRational rational = gVideoCodecCtx->time_base;
  
  
  
  LOGI(10, "numerator is %i", rational.num);
  
  LOGI(10, "denominator is %i", rational.den);
  
  LOGI(10, "duration is %d", gFormatCtx->duration);
  
  LOGI(10, "fps is %d", (double)av_q2d(rational));

  And here is the output :

  12-02 12:30:19.819: I/FFmpegTest(23903): numerator is 1
  
  12-02 12:30:19.819: I/FFmpegTest(23903): denominator is 180000
  
  12-02 12:30:19.819: I/FFmpegTest(23903): duration is 6594490
  
  12-02 12:30:19.819: I/FFmpegTest(23903): fps is 1692926992

  From the documentation I understand that the duration is meant to be "duration/time_base" which gives me 6594490 / 180000 = 36.6. The duration of my video file is 6 seconds and I do not know where this factor of 6 would come from.

  Also the framerate seems to be completely off.

  It is currenlty hard to find help as a lot of tutorials use deprecated methods and the documentation does not give examples.

  Any help would be appreciated.

  Thanks

  Edit :
  Thanks to the comment below I managed to print the following

  12-02 18:59:36.279: I/FFmpegTest(435): numerator is 1
  
  12-02 18:59:36.279: I/FFmpegTest(435): denominator is 180000
  
  12-02 18:59:36.279: I/FFmpegTest(435): duration is 6594490
  
  12-02 18:59:36.279: I/FFmpegTest(435): fps is 0.000006

  I also managed to find out a frame's timestamp in msec with this :

  int msec = 1000*(packet.pts * timeBase * gVideoCodecCtx->ticks_per_frame);

  This returns me something that's roughly 33fps (I expect 30). But I can't figure out how to retrieve the duration. The documentation says "duration of the stream, in AV_TIME_BASE fractional seconds" but 6594490 * 0.000006 = 39.5 - the correct duration is 6.3 seconds). Also the exact fps is 30 but nor sure how to get from 0.000006 to 30 with the above figures)

  Thanks