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• Merge commit ’106b62f4ba600f24415eaded5e020aeceb23fd59’

  28 mai 2014, par Michael Niedermayer

  Merge commit ’106b62f4ba600f24415eaded5e020aeceb23fd59’
  * commit ’106b62f4ba600f24415eaded5e020aeceb23fd59’ :
  
    matroskaenc : write the channel mask for FLAC
  Conflicts :
  
  	libavformat/matroskaenc.c
  Merged-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavformat/Makefile
  • [DH] libavformat/matroskaenc.c

• FFMPEG - Add (white, color-less, analog) grain to the video without desaturating video itself

  2 décembre 2018, par dd_code

  I am working on old videos where I am basically converting them to HVEC and sharpening, so i.e. my command can look like this

  .\ffmpeg.exe -i F:\file.mkv -vf unsharp=3:3:1.5 -c:v hevc_nvenc -qp 27 -a:c copy file_new.mkv

  inherent problem with this is, of course that with reducing bitrate and sharpening every now and then I can notice some nasty artifacts around the edges and on at plain-color objects.

  I noticed with some older, many times remastered movies/series that they have quite a lot of grain in the video, so I was thinking - what if I add grain and help it to mask the compression and sharpening artifacts ?

  After bit of searching I got to
  https://ffmpeg.org/ffmpeg-filters.html#noise
  and now I am using this command

  .\ffmpeg.exe -i F:\file.mkv -vf unsharp=3:3:1.5,noise=alls=14:allf=t+u -c:v hevc_nvenc -qp 30 -a:c copy file_new.mkv

  however this has one big problem, it is merely a digital RGB noise, is there a way to make it desaturated, analog-ish ? I tried adding h=s=0, however this is applying 0 saturation to the video track as a whole. Is there an effect which would achieve this or is there a way that I can reduce the saturation only of the very effect which then gets to "overlay" the video track, so the track would not be touched ?

• Recording MP3 file from iphone using FFMPEG

  16 octobre 2014, par harit shah

  I am trying to record an mp3 file from iphone. It seems it is not possible so next option I am trying is recording it with aac encoding and convert it with ffmpeg exe to mp3.

  I am recording the m4a file with following code :

  // Set the audio file
  
  NSArray *pathComponents = [NSArray arrayWithObjects:
  
                             [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject],
  
                             @"MyAudioMemo.aac",
  
                             nil];
  
  NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents];
  
  
  
  // Setup audio session
  
  AVAudioSession *session = [AVAudioSession sharedInstance];
  
  [session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];
  
  UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
  
  AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof (audioRouteOverride),&audioRouteOverride);
  
  
  
  NSMutableDictionary *recordSettings = [[NSMutableDictionary alloc] initWithCapacity:10];
  
  NSNumber *formatObject;
  
  formatObject = [NSNumber numberWithInt: kAudioFormatMPEG4AAC];
  
  
  
  [recordSettings setObject:formatObject forKey: AVFormatIDKey];
  
  [recordSettings setObject:[NSNumber numberWithFloat:44100.0] forKey: AVSampleRateKey];
  
  [recordSettings setObject:[NSNumber numberWithInt:1] forKey:AVNumberOfChannelsKey];
  
  // [recordSettings setObject:[NSNumber numberWithInt:12800] forKey:AVEncoderBitRateKey];
  
  // [recordSettings setObject:[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
  
  [recordSettings setObject:[NSNumber numberWithInt: AVAudioQualityHigh] forKey: AVEncoderAudioQualityKey];

  so when I try to convert it using ffmpeg -i 1.m4a 1.mp3 it says invalid input found while reading 1.m4a. I tried different encoding but everytime I get the same error. Any help on this would be life saving.

  Thanks.