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• ffmpeg : use a max variable to hold the maximum dts

  3 mai 2013, par Michael Niedermayer

  ffmpeg : use a max variable to hold the maximum dts
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] ffmpeg.c

• 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 :

• Truly live streaming to Android/iPhone

  4 juillet 2012, par Tsaukpaetra

  I have spent quite a while (past week) trying this to little avail. However, what I want seems completely unheard of. So far, I have reviewed recommendations available through google, which include encoding a static file into multiple static files in different formats, creating a playlist that hosts static files in an m3u8 file (files which get added to the playlist as streaming continues).
  I have also seen ideas involving rtmp, rtsp etc which are completely out of the question because of their incompatibility.
  Ideally, I would have one webpage that would link to the stream (http://server/video.mp4) and/or show it in a webpage (via the video tag). With that in mind, the most likely format would be h264+aac in mp4 container.

  Unfortunately, (and probably because the file has no duration metadata) it does not work. I can use a desktop player (such as VLC) to open the stream and play it, but my iPhone and Android both give their respective "Can't be played" messages.

  I don't think the problem is caused by the devices' ability to stream, for I have made a streaming shoutcast server work just fine (mp3 only).

  Currently, the closest I have become is using the following setup on my win32 machine :

  FFMPEG Command: : ffmpeg -f dshow -i video="Logitech Webcam 200":audio="Microphone (Webcam 200)" -b:v 180k -bt 240k -vcodec libx264 -tune zerolatency -profile:v baseline -preset ultrafast -r 10 -strict -2 -acodec aac -ac 2 -ar 48000 -ab 32k -f flv "udp ://127.0.0.1:1234"

  VLC: : Stream from udp ://127.0.0.1:1234 to http:// :8080/video.mp4 (No Transcoding), basically just to convert the UDP stream into an http-accessible stream.

  Any hints or suggestions would be warmly welcomed !