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• Converting video files from mp4 to webM for playing using Media Source Extensions

  19 octobre 2018, par raul

  I’m currently trying to implement a video player using Media Source Extensions. Currently just a very simple proof of concept, following a tutorial I found here.

  I cloned their repo with all source code from github here and am testing the implementation on Chromium and Firefox with various video files.

  Everything worked well with the example webm files in the repo for both browsers.

  Next I tried to convert a video I downloaded from some random site using ffmpeg and mse-tools to "align the clusters" of the webm file using the following commands :

  ffmpeg -i randomvideo.mp4 -c:v libvpx -c:a libvorbis output.webm
  
  mse_webm_remuxer output.webm aligned.webm

  Again, all was well on both browsers.

  Finally, I wanted to convert a very simple animation I created in blender (rendered with h264 in mp4).

  I tried converting the resulting file using the same process as above and the file played normally on firefox, but did not load on chromium.

  I assume I am commiting some error when converting the file, but inspecting the attributes of the final file with vlc and ffprobe, I could not find any obvious problems.

  Any ideas as to what I am doing wrong ?

  One final test I did was to go to this site to get some sample webm files.

  I downloaded the "Big Buck Bunny Trailer in WebM" and "Elephants Dream as WebM File".

  Both files worked in firefox, but the "Elephants Dream" file would not play in chromium.

  I am on a linux machine (Arch Linux distro) with the following versions of the browsers :

  Chromium Version 69.0.3497.100 (Official Build) Arch Linux (64-bit)

  Firefox 62.0.3 (64-bit)

  I have shared the file I created from the blender animation (very small - only 36 KB) on google drive here in case anyone wants to check it out.

• Permission denied with JAVE on OSX

  18 octobre 2016, par clankill3r

  I try to convert video to audio using jave on OSX.

  http://www.sauronsoftware.it/projects/jave/manual.php

  As the documentation states

  ...You can even build it by yourself getting the code (and the
  documentation to build it) on the official ffmpeg site. Once you have
  obtained a ffmpeg executable suitable for your needs, you have to hook
  it in the JAVE library. That’s a plain operation.

  I builded ffmpeg, but running the code I get a Permission denied error.
  I even changed all file permissions to 777 recursive.
  Hope someone can help, the documentation and error messages are very unclear.

  public class Mp4ToSoundTest {
  
  
  
  
  
      public static void main(String[] args) {
  
          Mp4ToSoundTest a = new Mp4ToSoundTest();
  
          a.setup();
  
      }
  
  
  
      void setup() {
  
  
  
          File source = new File("/Users/doekewartena/Downloads/vids_future_proj/VID_20160523_180100.mp4");
  
  
  
          System.out.println(source.exists());
  
  
  
          FFMPEGLocator my_ffmpeg_locator = new FFMPEGLocator() {
  
              @Override
  
              protected String getFFMPEGExecutablePath() {
  
                  return "/Users/doekewartena/Downloads/ffmpeg-3.1.4";
  
              }
  
          };
  
  
  
  
  
          File target = new File("/Users/doekewartena/Downloads/vids_future_proj/VID_20160523_180100.mp3");
  
          AudioAttributes audio = new AudioAttributes();
  
          audio.setCodec("libmp3lame");
  
          audio.setBitRate(128000);
  
          audio.setChannels(2);
  
          audio.setSamplingRate(44100);
  
          EncodingAttributes attrs = new EncodingAttributes();
  
          attrs.setFormat("mp3");
  
          attrs.setAudioAttributes(audio);
  
          Encoder encoder = new Encoder(my_ffmpeg_locator);
  
  
  
          // The source file can't be decoded. It occurs when the source file container, the video stream format or the
  
          // audio stream format are not supported by the decoder. You can check for supported containers and plugged
  
          // decoders calling the encoder methods getSupportedDecodingFormats(), getAudioDecoders() and getVideoDecoders().
  
          try {
  
              String[] r = encoder.getSupportedDecodingFormats();
  
              System.out.println("a");
  
              for (String s : r) {
  
                  System.out.println(s);
  
              }
  
              System.out.println("b");
  
  
  
              System.out.println();
  
              System.out.println(encoder.getAudioDecoders());
  
  
  
          } catch (EncoderException e) {
  
              e.printStackTrace();
  
          }
  
  
  
  
  
  
  
          try {
  
              encoder.encode(source, target, attrs);
  
          } catch (EncoderException e) {
  
              e.printStackTrace();
  
          }
  
          System.out.println("done");
  
  
  
      }
  
  
  
  }

• Cannot Play Video Output of Libavcodec (ffmpeg) Encoding Example

  29 octobre 2019, par user3707763

  From FFMPEG’s GitHub, I use the encode_video.c to generate a 1 second video. Here is the example in question : https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/encode_video.c

  I compile with : gcc -Wall -o ffencode encode_video.c -lavcodec -lavutil -lz -lm

  Clean compile, zero warnings.

  I test the program by running : ./ffencode video.mp4 libx264

  Lots of stats printed out (expected based on source code) as well as ffmpeg logs, but ultimately no errors or warnings.

  However, then the generated output video.mp4, can only be played by ffplay, and VLC Player (as well as Google Chrome) fail to play the video.

  Playing it via vlc command line actually prints :

  [00007ffd3550fec0] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
  
  TagLib: MP4: Invalid atom size
  
  TagLib: MP4: Invalid atom size
  
  TagLib: MP4: Invalid atom size

  Looking at ffprobe output, the bitrate and duration fields are empty :

  Input #0, h264, from 'video.mp4':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: h264 (High), yuv420p(progressive), 352x288, 25 fps, 25 tbr, 1200k tbn, 50 tbc

  I am using ffmpeg 4.1 with the following configuration :

  ffprobe version 4.1 Copyright (c) 2007-2018 the FFmpeg developers
  
    built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gpl --enable-libmp3lame --enable-libopus --enable-libsnappy --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-opencl --enable-videotoolbox
  
    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
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100

  Any ideas how to fix this ? It is pretty surprising to see an API’s official example to be lacking such basic information.