Recherche avancée

Sur d’autres sites (10725)

• Does android support .m4a metadata ?

  23 octobre 2016, par David Barishev

  Im using taglib-sharp-portable to tag audio files in my app. My audio files are .acc, which are inboxed in a .m4a format.
  I have no option but to use this format, since i’m extracting the audio from a Video file (.mp4/.webm), based on using this SO answer. I can’t re encode the music stream, since it will take a lot of time on an cellular device.
  The problem i’m facing is that the music player doesn’t recognize the tags, even though they are tagged correctly. If i pull the file from the device, and view it on my Windows PC, i can see the tags fine.

  Here is the code im using to tag the file :

  public static async Task tagFile(File musicFile, string name, string songID, Context c, SongDownloadNotification nf = null)
  
  { 
  
              var imageFilePath = await DownloadThumbnailImage(songID, c, nf);
  
              string[] songDetails = GetSongDetails(name);
  
  
  
              Log.Verbose(tag, "Exstraced song Details. Artist Name: {0}, Song Name: {1}", songDetails[0], songDetails[1]);
  
  
  
              var fsMusic = new System.IO.FileStream(
  
                  musicFile.CanonicalPath,
  
                  System.IO.FileMode.Open,
  
                  System.IO.FileAccess.ReadWrite,
  
                  System.IO.FileShare.ReadWrite,
  
                  4096,
  
                  true);
  
  
  
              TagLib.File tagFile = TagLib.File.Create(new TagLib.StreamFileAbstraction(musicFile.CanonicalPath, fsMusic, fsMusic));
  
  
  
              tagFile.Tag.Clear();
  
  
  
              tagFile.Tag.Performers = new[] { songDetails[0] };
  
              tagFile.Tag.AlbumArtists = new[] { songDetails[0] };
  
              tagFile.Tag.Title = songDetails[1];
  
              tagFile.Tag.Album = songDetails[1];
  
  
  
              var fsImage = new System.IO.FileStream(
  
                  imageFilePath,
  
                  System.IO.FileMode.Open,
  
                  System.IO.FileAccess.ReadWrite,
  
                  System.IO.FileShare.ReadWrite,
  
                  4096,
  
                  true);
  
  
  
              tagFile.Tag.Pictures = new[] { new TagLib.Picture(new TagLib.StreamFileAbstraction(musicFile.CanonicalPath, fsImage, fsImage)) };
  
  
  
              tagFile.Save();
  
              Log.Debug(tag, "Succesfully added tags to file");
  
  
  
              fsMusic.Close();
  
              fsImage.Close();
  
  
  
              if (!new File(imageFilePath).Delete())
  
                  Log.Warn(tag, "Couldnt delete tmp file");
  
              else
  
                  Log.Verbose(tag, "Deleted thumbnail file succesfully");
  
  } 

  These question came to me :

  • Is my choice of encapsulating the raw .acc file in .m4a file good ? The format im looking into, is audio only, is .m4a overkill for it ?
  • Does android support reading tags of .m4a file ? If so what did i do wrong with my code ?If not, how can i add tags to .acc ( or some other ’parent’ format), that android supports, and i would not need to re encode it ?

• aacenc : implement the complete AAC-Main profile

  21 août 2015, par Rostislav Pehlivanov

  aacenc : implement the complete AAC-Main profile
  This commit finalizes AAC-Main profile encoding support
  
  by implementing all mandatory and optional tools available
  
  in the specifications and current decoders.
  The AAC-Main profile reqires that prediction support be
  
  present (although decoders don’t require it to be enabled)
  
  for an encoder to be deemed capable of AAC-Main encoding,
  
  as well as TNS, PNS and IS, all of which were implemented
  
  with previous commits or earlier of this year.
  Users are encouraged to test the new functionality using either
  
   profile:a aac_main or -aac_pred 1, the former of which will enable
  
  the prediction option by default and the latter will change the
  
  profile to AAC-Main. No other options shall be changed by enabling
  
  either, it’s currently up to the users to decide what’s best.
  The current implementation works best using M/S and/or IS,
  
  so users are also welcome to enable both options and any
  
  other options (TNS, PNS) for maximum quality.
  Signed-off-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  

  • [DH] libavcodec/Makefile
  • [DH] libavcodec/aac.h
  • [DH] libavcodec/aaccoder.c
  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/aacenc.h
  • [DH] libavcodec/aacenc_pred.c
  • [DH] libavcodec/aacenc_pred.h

• WebRTC books – a brief review

  30 décembre 2013, par silvia

  I just finished reading Rob Manson’s awesome book “Getting Started with WebRTC” and I can highly recommend it for any Web developer who is interested in WebRTC.

  Rob explains very clearly how to create your first video, audio or data peer-connection using WebRTC in current Google Chrome or Firefox (I think it also now applies to Opera, though that wasn’t the case when his book was published). He makes available example code, so you can replicate it in your own Web application easily, including the setup of a signalling server. He also points out that you need a ICE (STUN/TURN) server to punch through firewalls and gives recommendations for what software is available, but stops short of explaining how to set them up.

  Rob’s focus is very much on the features required in a typical Web application :

  • video calls
  • audio calls
  • text chats
  • file sharing

  In fact, he provides the most in-depth demo of how to set up a good file sharing interface I have come across.

  Rob then also extends his introduction to WebRTC to two key application areas : education and team communication. His recommendations are spot on and required reading for anyone developing applications in these spaces.

  —

  Before Rob’s book, I have also read Alan Johnson and Dan Burnett’s “WebRTC” book on APIs and RTCWEB protocols of the HTML5 Real-Time Web.

  Alan and Dan’s book was written more than a year ago and explains that state of standardisation at that time. It’s probably a little out-dated now, but it still gives you good foundations on why some decisions were made the way they are and what are contentious issues (some of which still remain). If you really want to understand what happens behind the scenes when you call certain functions in the WebRTC APIs of browsers, then this is for you.

  Alan and Dan’s book explains in more details than Rob’s book how IP addresses of communication partners are found, how firewall holepunching works, how sessions get negotiated, and how the standards process works. It’s probably less useful to a Web developer who just wants to implement video call functionality into their Web application, though if something goes wrong you may find yourself digging into the details of SDP, SRTP, DTLS, and other cryptic abbreviations of protocols that all need to work together to get a WebRTC call working.

  —

  Overall, both books are worthwhile and cover different aspects of WebRTC that you will stumble across if you are directly dealing with WebRTC code.