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• WMA Lossless and ProRes Encoder

  4 mars 2012, par Multimedia Mike — General

  The projects (FFmpeg / Libav) just got a WMA lossless decoder. For those keeping score, this means that there are open source methods for decoding every single one of Microsoft’s proprietary audio codecs (Windows Media Audio, or WMA) : WMA v1, WMA v2, WMA9/Pro, WMA Voice, and now WMA lossless. Currently, it’s only advertised to decode 16-bit audio (no 24-bit). Also, when I first tried it a few days ago, it didn’t decode the very end of the single sample file I concocted many years ago (luckynight.wma). But that might be cleared up by now.

  Some other recent developments in the projects that I wanted to call out : An encoder for the Apple ProRes encoder from Kostya ; XWD (X window dump) image decoding and encoding from Paul B. Mahol ; a Sun rasterfile encoder from Aneesh Dogra.

  And then there’s the new playback system for CDXL files, also courtesy of Paul B. Mahol. I wasn’t familiar with this format until I wrote this post, which is surprising, given the format’s vintage. This was a CD-ROM FMV format favored for Amiga computers. Here it is in all its 160x120x10fps glory :

  
  
  

  That’s the amigaball.cdxl sample available in the repository. The sample is 3835910 bytes large and plays for about 24 seconds. This yields a data rate of about 159 kbytes/second. So, yeah, single-speed CD-ROM FMV.

• How to increase video encoding speed in ffmpeg ?

  16 octobre 2017, par Ashutosh Tiwari

  I am recording video clips and then joining all the clips in a final video.
  Everything goes fine but the joining process takes too long.

  Tried to using some ffmpeg filters from here :
  https://trac.ffmpeg.org/wiki/Encode/H.264

  And here is my ffmpeg command that I am using to increase the speed (which seems to be wrong) :

  command = new String[]{"-y",
  
                  "-f",
  
                  "concat",
  
                  "-safe",
  
                  "0",
  
                  "-i",
  
                  "/storage/emulated/0/DCIM/my_file.txt",
  
                  "-c:v",
  
                  "-preset",
  
                  "fast",
  
                  "-crf",
  
                  "22",
  
                  "copy",
  
                  "-flags",
  
                  "+global_header",
  
                  "/storage/emulated/0/DCIM/SampleApp/" + videoOutputPath
  
          };

  Please help ! Thanks much.

• Android : Build a decoder library from Jpeg to MP4 video

  9 juillet 2014, par Ilya_Gazman

  I am working on Android 2.2, and my goal is to covert a sequence of images to mp4 video, MPEG-4_Part_14, to be more exact.

  The most reasonable solution would be using FFmpeg libraries, and compile them to Android using NDK. How ever I am looking for solution without NDK.

  I do not expect from you to build this tool for me, or find some one else who did. I spent quit of time now searching for that, and it’s some thing that probably no1 one did yet.

  So the only thing that I am asking, is help me find the specs so I be able to build the decoder by my self. I know that it’s not a trivial task(May be this is why no one did it yet), but I want to do it any way. So please just help me start it.