[FFmpeg-trac] #1604(undetermined:new): Rtmp streaming fps continually drops

FFmpeg trac at avcodec.org
Fri Aug 10 15:54:59 CEST 2012


#1604: Rtmp streaming fps continually drops
-------------------------------------+-------------------------------------
             Reporter:  Pyriel0      |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:  rtmp         |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------

Comment (by Pyriel0):

 The command line I used for what is pasted is at the very top. Here are
 some examples.
 I used this command line to record to the hard drive first and it works
 fine. Then I changed the output from f:\testing.mp4 to -f flv "rtmp
 ://live-dfw.justin.tv/app/xxxxxx".

 {{{
 ffmpeg -re -y -rtbufsize 100000k -f dshow -i video="SCFH DSF":audio="Line
 1 (Virtual Audio Cable)" -pix_fmt yuv420p -s hd720 -vcodec libx264 -preset
 medium -maxrate 2400k -bufsize 600k -acodec libmp3lame -ac 2 -b:a 128k
 f:\testing.mp4
 }}}

 I used the 32 bit 7-30-2012 zeranoe version. Forgot the 32 bit does not
 pick up virtual audio cable so the first 3 examples do not have audio. For
 the last video "2400k test 3 audio", I changed the audio to "virtual-
 audio-capturer" so there would be sound. 2400kb test 1 and 2 are the same,
 I only ran it again because I forgot how low the fps went on the first
 run.

 http://www.twitch.tv/pyriel0/videos

 2400k tests were done using the bitrates in the commnad line. 1500k used
 1500k maxrate and 500k buffer. The 1500k streaming held 30 fps. 2400k
 dropped down to 12 fps. The audio remains stable in the final 2400kb test
 when the video is choppy. I doubt there is a latency problem since the
 audio does not get messed up.

 System ram usage:
 Game only: ~3.5 GB
 Recording to hard drive: ~3.8 GB
 Streaming 1500k: ~4 GB
 Streaming 2400kb: ~5 GB

 I can only use the 32 bit version for these tests because the 64 bit uses
 all available ram which causes everything to stutter.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1604#comment:9>
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