Recherche avancée

Sur d’autres sites (6993)

• What is the meaning of the hexadecimal value that follows the avc1 in an m3u8 variant playlist

  16 février 2013, par Anand

  From this apple's sample variant playlist

  https://devimages.apple.com.edgekey.net/resources/http-streaming/examples/bipbop_4x3/bipbop_4x3_variant.m3u8

  i see hexadecimal numbers follow the av1 like avc1.4d4015,avc1.4d401e,avc1.4d401e,avc1.4d401f can anybody know what is the meaning of them

• ffmpeg with a set of image files not formatted as %d.jpg

  12 juin 2012, par Rob Lourens

  I'm using ffmpeg to compile a set of jpgs into a video. There is plenty written about this, but it seems that the only way to do it is to have images named as consecutive padded numbers, e.g. 0001.jpg, 0002.jpg...

  The ffmpeg documentation states that it is possible to use other types of patterns, such as %*.jpg to capture all *.jpg files, but the only pattern that I have gotten to work on my own is the %0Nd-type pattern. The man page only mentions that type.

  I really want to have ffmpeg use a set of images with arbitrary names. It would simplify my app quite a lot, make it easier to keep thumbnails and metadata in sync as images are inserted and deleted, etc. Creating links is not an option since I'm working on Android. Is there any way to do this ?

  I'm also willing to modify the ffmpeg source or work with the C api to get it to do what I want, but I can't find the right spot in the code to do it, or appropriate docs for the C api. Any advice ? Thanks.

• Http Live Streaming EXT-X-STREAM-INF, Calculating BANDWITH

  26 juin 2012, par Agzam

  Initially I've tried to find possible ways to do HLS segmenting on other non-Mac platforms.

  Segmenting videos for HLS involves the following steps :

  1) Splitting the encoded video into segments

  2) Creating playlist (.m3u8) file that simply contains list of segments for the current rendition, including duration in seconds for each segment

  3) Creating a variant playlist that contains relative paths to all playlists of all renditions with the information about BANDWITH which according to HTTP Live streaming protocol is :

  The value is a decimal-integer of bits per second. It MUST be an upper bound of the overall bitrate of each media segment (calculated to include container overhead) that appears or will appear in the Playlist.

  Latest version of ffmpeg includes possibilities of splitting videos. However ffmpeg can’t create m3u8 files. Creating simple playlist not a problem. But creating variant playlist might be :

  So variantplaylistcreator on Mac creates those, calculates somehow bitrates and puts value based on that into BANDWITH tag.

  I’ve tried many different ways but yet I couldn’t get exactly the same numbers that variantplaylistcreator does, and at this point I can’t find any information how exactly it calculates those values and what algorithm it uses.
  My numbers are close, but still slightly different.

  In theory it should not be a problem, but the point is - I don’t know that for sure.
  Maybe the BANDWITH information should be precise for flawless video playing, maybe it doesn’t have to.

  Anyway I'm really curious how exactly variantplaylistcreator calculates them :