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• Returns wrong frame while seeking in FFMPEG Player

  5 février 2015, par user543

  I have implemented an audio player which supports all the formats using FFMPEG. But while seeking the audio, the application is getting the wrong frame at that target duration. Here is my code for the seek functionality.

           int64_t seekTime = av_rescale_q(seekValue * AV_TIME_BASE,
  
                      AV_TIME_BASE_Q,
  
                      fmt_ctx->streams[seekStreamIndex]->time_base);
  
  
  
              int64_t seekStreamDuration =
  
                      fmt_ctx->streams[seekStreamIndex]->duration;
  
  
  
              int flags = AVSEEK_FLAG_BACKWARD;
  
              if (seekTime > 0 && seekTime < seekStreamDuration)
  
                  flags |= AVSEEK_FLAG_ANY;
  
  
  
              int ret = av_seek_frame(fmt_ctx, seekStreamIndex, seek_target,
  
                      flags);
  
  
  
              if (ret < 0)
  
                  ret = av_seek_frame(fmt_ctx, seekStreamIndex, seekTime,
  
                          flags);
  
  
  
            avcodec_flush_buffers(dec_ctx);

  It is working fine for most of the songs.
  But some of the mp3 songs are getting the wrong timespan.

  For instance : If the song total duration is 2 minutes, if I play the song without seeking it works fine. But while playing, if we seek the song to some position, this will make the song ends with 2 mins and 10 seconds.

  I am getting this issue with only mp3 songs. I am using FFMPEG 2.1. The code for the seek functionality is working fine on FFMPEG 0.11.1.

  Please provide any information about this issue.

• Making a thumbnail using fluent-ffmpeg returns ffprobe

  29 avril 2019, par user10204157

  I am getting the following error :

  Error: ffprobe exited with code 1
  
  ffprobe version 4.1.1 Copyright (c) 2007-2019 the FFmpeg developers
  
    built with gcc 8.2.1 (GCC) 20190212
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass
  
  --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  [tcp @ 0000020813d01740] Connection to tcp://stemuli.blob.core.windows.net:443 failed: Error number -138 occurred  <------
  
  https://stemuli.blob.core.windows.net/stemuli/mentor-lesson-video-76cbf390-4033-4a92-b127-7df22d5885f8.MOV: Unknown error

  Does this mean that azure’s connection is just being cut off ?

• webm files created with ffmpeg are too long

  6 août 2022, par Azrael

  I have a folder of exactly 300 images in png format (labelled 1.png, 2.png, ..., 300.png), which I'm trying to convert to a video. I would like the video to be in the webm format, but there seems to be an issue :

  


  using the following command :

  


  ffmpeg -start_number 1 -i ./frames/%d.png -frames:v 300 -r 30 out.webm


  


  does generate an out.webm file, and, according to ffprobe -select_streams v -count_frames -show_entries stream=nb_read_frames,r_frame_rate out.webm (which is presumably quite an inefficient way to get that information, but that's besides the point), it does contain 300 frames and has a framerate of exactly 30/1, however, instead of the expected exactly 10 seconds (from 300 frames being played at 30 fps), the video lasts slightly longer (about 12 seconds).
  
This discrepancy does seem to scale up with video length ; 900 frames being converted to a video the same way and with the same frame rate yield a 36 (instead of 30) second video.

  


  For testing, I also tried generating an mp4 file instead of a webm one, with the following command (exact same as above, but out.mp4 instead of out.webm), and that worked exactly as expected, out.mp4 was a 10-second long video.

  


  ffmpeg -start_number 1 -i ./frames/%d.png -frames:v 100 -r 30 out.mp4


  


  How do I fix this ? is my ffmpeg command off or is this a bug within the tool ?