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• ffmpeg conditional copy or encode audio stream

  31 octobre 2017, par PieterV

  My objective is to DirectPlay all my content in Plex.
  To do this, I have to conditionally re-encode some audio and video streams, to a format that can be played without the server having to transcode on the fly.

  I am currently using HanbrakeCLI to encode video to x264 and audio to a compatible format.

  I use the "—aencoder copy —audio-fallback ac3" options, to copy the audio stream as is if in a supported format, i.e. aac/ac3/eac3/truehd/dts/dtshd/mp3/flac, or to encode to ac3 if not a supported format.

  I want to switch away from HandbrakeCLI because it does not support copying video streams, sometimes my media has a good video stream, but the audio needs to be encoded only, e.g. WMV with a VC1 video and WMAPro audio stream.

  A commandline for HandbrakeCLI looks like :

      // Create the HandbrakeCLI commandline and execute
  
      // https://handbrake.fr/docs/en/latest/cli/cli-guide.html
  
      string commandline = $"--input \"{inputname}\" --output \"{outputname}\" --format av_mkv --encoder x264 " +
  
                           $"--encoder-preset medium --quality {Settings.Default.VideoEncodeQuality} --subtitle 1,2,3,4 --audio 1,2,3,4 " +
  
                           $"--aencoder copy --audio-fallback ac3";

  In ffmpeg I would use :

      // Create the FFmpeg commandline and execute
  
      // https://trac.ffmpeg.org/wiki/Encode/H.264
  
      string commandline = $"-i \"{inputname}\" -c:v libx264 -crf {Settings.Default.VideoEncodeQuality} -preset medium -c:a copy -f matroska \"{outputname}\"";

  Is there an equivalent to HandbrakeCLI’s "—audio-fallback ac3" in ffmpeg ?

  I.e. I want the video to be encoded to x264, all audio tracks copied if the track is aac or ac3 or eac3 or truehd or dts or dtshd or mp3 or flac, and if not, encoded as ac3, while also copying all the subtitles and chapters as is.

• Failing to convert audio file from M4A to MP3 format using FFmpegWrapper

  7 octobre 2016, par Radu Matei

  I’m trying to convert a M4A audio file to MP3 format using ffmpeg in an iOS Project, language : Objective C. To make things easier I try to accomplish this using FFmpegWrapper

  I’m using ffmpeg ver 2.8.3 and FFmpegWrapper 1.0 installed via CocoaPods. On pod outdated it shows that I’m using latest versions.

  This is my code :

  - (void) convertMP4ToMP3
  
  {
  
      NSString *inputFormat = @"m4a";
  
      NSString *outputFormat = @"mp3";
  
  
  
      NSString *inputFileName = @"audio";
  
      NSString *outputFileName = @"outputAudio";
  
  
  
      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
  
      NSString *documentsDirectory = [paths objectAtIndex:0];
  
      NSString *inputFilePath = [[NSBundle mainBundle] pathForResource:inputFileName ofType:inputFormat];
  
      NSString *outputFilePath = [documentsDirectory stringByAppendingPathComponent:[outputFileName stringByAppendingPathExtension:outputFormat]];
  
  
  
      if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath])
  
      {
  
          [[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil];
  
      }
  
  
  
      FFmpegWrapper *wrapper = [[FFmpegWrapper alloc] init];
  
      NSDictionary *options = @{kFFmpegInputFormatKey : inputFormat, kFFmpegOutputFormatKey : outputFormat};
  
      [wrapper convertInputPath:inputFilePath outputPath:outputFilePath options:options progressBlock:^(NSUInteger bytesRead, uint64_t totalBytesRead, uint64_t totalBytesExpectedToRead) {
  
      } completionBlock:^(BOOL success, NSError *error) {
  
  
  
          success ? NSLog(@"Success!") : NSLog(@"Error : %@",error.localizedDescription);
  
      }];
  
  }

  And as result conversion fails with the following logs :

  [mp3 @ 0x16a5ca00] Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead.
  
  [mp3 @ 0x16a5ca00] Invalid audio stream. Exactly one MP3 audio stream is required.
  
  Error : Invalid argument

  Any help would be appreciated.

• avdevice/decklink : 10 Bit support for Decklink input device

  18 janvier 2015, par Georg Lippitsch

  avdevice/decklink : 10 Bit support for Decklink input device
  Example to capture video clip at 1080i50 10 bit :
  
  ffmpeg -bm_v210 1 -f decklink -i ’UltraStudio Mini Recorder@11’ -acodec copy -vcodec copy output.avi
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavdevice/decklink_common_c.h
  • [DH] libavdevice/decklink_dec.cpp
  • [DH] libavdevice/decklink_dec_c.c