Recherche avancée

Sur d’autres sites (7569)

• VP8 Documentation and Test Vector Contributions

  14 octobre 2010, par noreply@blogger.com (John Luther)

  Janne Salonen of the WebM team in Oulu, Finland (formerly On2 Finland) has added a tabular description of the VP8 syntax to the VP8 Bitstream Guide. The new annex provides a concise reference of the elements in the bitstream and we hope will make implementing and testing VP8 decoders easier. The updated document and source can be downloaded from our documentation page.

  We’re working on more improvements to the bitstream guide and invite other community members to help. As with the VP8 code, we gladly give attribution credit to documentation contributors and have added an AUTHORS file to the bitstream-guide Git repository.

  New VP8 Test Vectors

  The Oulu team has also produced some new VP8 test vectors. We analyzed a large set of WebM videos and produced two important corner use cases. The first produces the worst-case memory bandwidth (i.e., lots of global motion, all fractional motion vectors). The second produces the worst-case boolean decoder bin rate over dozens of consecutive frames. These vectors have been added to the VP8 test repository. Our team will consider other corner cases in the next batch of streams we add to the repository.

  Aki Kuusela is Hantro Embedded Engineering Manager at Google.

  

• Codec profile of AAC media file [closed]

  9 janvier 2013, par Pavle

  I need to find out codec profile of some AAC media file. (I want to know if that file iz HE-ACC or some other codec profile).

  I tried with source like this :

  AVFormatContext* pFormatCtx;
  
  avformat_open_input(pFormatCtx, input_path, NULL, NULL);
  
  ..
  
  avformat_find_stream_info((*pFormatCtx), NULL);
  
  ..
  
  /* I hope i'll get FF_PROFILE_AAC_MAIN or FF_PROFILE_AAC_LOW or FF_PROFILE_AAC_HE ... */
  
  int wanted_profile = pFormatCtx->streams[audio_stream_index]->codec->profile;
  
  
  
  /* but I always get FF_PROFILE_UNKNOWN :( */

  Can anyone help me to find out how to do it, please.

• What could change the fps when copying frames from mp4 file to mp4 without reencoding ?

  27 novembre 2012, par theateist

  I try to copy video from in.mp4 to out.mp4 without reincoding. I'm using the code example suggested by pogorskiy here. The copy process success, but the video is played very fast. I checked the fps of both files with MediaInfo. The fps of "in.mp4" is 25 fps and "out.mp4" it 533fps. I don't understand what changing the fps to 533 if I construct outStream from inStream ?

  I hope I explained myself correctly.