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• ffmpeg rtmp webcam live stream iphone/pad segment size too big

  1er février 2013, par Foo Barazz

  I'm transcoding a rtmp stream from a red5 server for use to live stream on a iphone or ipad device. I built latest ffmpeg version from git repo using the built in segmenter to create .ts files and m3u8 playlist file using the following :

  ffmpeg -probesize 50k -i "rtmp://localhost/oflaDemo/red5StreamDemo live=1" \
  
  -c:v libx264 -b:v 128k -vpre ipod320 -flags -global_header -map 0 \
  
  -f segment -segment_time 3 -segment_list foo.m3u8 -segment_list_flags +live \
  
  -segment_list_type m3u8 -segment_list_size 5 -segment_format mpegts foo%d.ts

  This works fine, but I can't get the segment size smaller than about 12 sec even set to 3 (-segment_time 3). It seems to be caused by libx264 vcodec.
  Am I missing any flag ?

  By the way, you can simple run the ffmpeg command above successfully by starting red5 SimpleBroadcaster example.

• Revision 734c5ffa2c : Apply constrained partition search range to non-RD mode decision This commit en

  23 avril 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_encodeframe.c

  
  
  Apply constrained partition search range to non-RD mode decision

  This commit enables a chessboard pattern for partition search. All
  the black blocks run regular partition search ranging from 8x8 to
  32x32. The rest white blocks take the nearby blocks’ information
  to adaptively decide the effective search range.

  The compression performance for rtc set at speed -5 is down by 1.5%.
  For pedestrian 1080p at speed -5, the runtime goes from 41594 ms to
  39697 ms, i.e., about 5% faster.

  Change-Id : Ia4b96e237abfaada487c743bca08fe1afd298685

• Is "begin" param dead in Youtube's *.c.youtube.com/videoplayback ?

  23 janvier 2013, par Minime

  I tested Youtube video download with begin param using ytdl, and realized that it's not working properly. Below is an URL with begin param. (It won't work on your side because it's session-IP address based.)

  http://r4---sn-o097znee.c.youtube.com/videoplayback?ratebypass=yes&cp=U0hUTVNOT19JTENONF9LSFNIOmtjaWozaFd5Vnhl&newshard=yes&source=youtube&ipbits=8&fexp=916600%2C906072%2C923114%2C914093%2C916626%2C920704%2C912806%2C922403%2C922405%2C929901%2C913605%2C925710%2C929104%2C929110%2C908493%2C920201%2C913302%2C919009%2C911116%2C926403%2C910221%2C901451&id=58dafac107cd7cae&key=yt1&mt=1358307193&gcr=us&ms=au&itag=46&upn=efQT2cDue5M&ip=xxxx&sparams=cp%2Cgcr%2Cid%2Cip%2Cipbits%2Citag%2Cratebypass%2Csource%2Cupn%2Cexpire&expire=1358331742&sver=3&mv=m&signature=C957313FEC2AC174F72CEFE52BF663ABAC8D0E4B.27F8485A36BE654CA25D3CA75A927D443523CA68&begin=12000

  I traced Youtube site by myself to see if there are any recent changes on their black boxed
  API. And I found that begin param is no longer put in videoplayback, but put in user_watch as below.

  http://www.youtube.com/user_watch?video_id=-YFiHW59ASs&ptk=StyleHaul&referrer=None&t=vjVQa1PpcFPiDK6v9s-rWrDn8gNv0QvpjyCIjiAgsm0=&asv=3&fmt=34&cpn=BOOMP-Bzbv1jikj9&el=detailpage&plid=AATTaqGSIR9CQ-MJ&begin=70000

  Its response is

  <?xml version="1.0" encoding="utf-8"?>

  And videoplayback only has range param, which indicate byte range where to pull. However, I couldn't figure out exact mechanism how new begin param works.

  http://r8---sn-p5q7yne6.c.youtube.com/videoplayback?algorithm=throttle-factor&burst=40&cp=U0hUTVNSVl9IT0NONF9LTFpGOlY5MU5RYVYtWHFw&cpn=BOOMP-Bzbv1jikj9&expire=1358378535&factor=1.25&fexp=919361%2C910207%2C916612%2C913112%2C912806%2C922403%2C922405%2C929901%2C913605%2C925710%2C929104%2C929110%2C908493%2C920201%2C913302%2C919009%2C911116%2C910221%2C901451&gcr=us&id=f981621d6e7d012b&ip=xxxx&ipbits=8&itag=34&keepalive=yes&key=yt1&ms=au&mt=1358354777&mv=m&newshard=yes&ratebypass=yes&signature=AA38C7074D8FA9DA44D01D9BB3675C78D05B9794.66D67C5AB111D8FB9EC3C8A141BBB11D9D70545D&source=youtube&sparams=algorithm%2Cburst%2Ccp%2Cfactor%2Cgcr%2Cid%2Cip%2Cipbits%2Citag%2Csource%2Cupn%2Cexpire&sver=3&upn=aLby9GtO0sU&range=3563520-5345279

  Can anyone explain how to pull a video starting from specific position(msec) in new API ?