[FFmpeg-user] ffmpeg live stream transcoding
dan at streemit.net
Wed Jul 25 20:30:08 CEST 2012
On 07/25/2012 06:31 AM, radiocm wrote:
> I will be very glad if someone would have an opportunity to offer such a
> tutorial. Because the tutorial from Wowza website keep me unclear. Thank you
> for your receptivity.
> Best regards, Vadim.
> View this message in context: http://ffmpeg-users.933282.n4.nabble.com/ffmpeg-live-stream-transcoding-tp4652003p4652047.html
> Sent from the FFmpeg-users mailing list archive at Nabble.com.
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
I can't really offer a tutorial, but I can show you how I did something
In my application, I have a server running vlc sucking streams from some
cameras, encoding them as MPEG2 streams and sending them to ports 5000
through 5003 on my intermediary server (I'll have to let someone else
explain how to set that up, as that was someone else's part of the
project). I have another server running Wowza, with an instance named
"live". And I've got an intermediate server that sucks in MPEG2 streams
coming in on ports 5000 to 5003, transcoding them into mp4 streams with
H.264 and AAC codecs, and pushing the transcoded streams on to Wowza.
The command line I use to pull the stream from port 5000, transcode it,
and push it is:
ffmpeg -i 'udp://localhost:5000?fifo_size=1000000&overrun_nonfatal=1'
-crf 30 -preset ultrafast -acodec aac -strict experimental -ar 44100 -ac
2 -b:a 96k -vcodec libx264 -r 25 -b:v 500k -f flv 'rtmp://<wowza server
-i 'udp://localhost:5000?fifo_size=1000000&overrun_nonfatal=1' tells
ffmpeg where to pull the input stream from. The parts after the ? are
probably not needed most of the time, but I did need it after all.
-crf 30 sets the Content Rate Factor. That's an x264 argument that tries
to keep reasonably consistent video quality. A value of 30 allows
somewhat lower quality and bit rate.
-preset ultrafast as the name implies provides for the fastest possible
encoding. If some tradeoff between quality and encode speed, go for the
speed. This might be needed if you are going to be transcoding multiple
streams on one machine.
-acodec aac sets the audio codec
-strict experimental allows use of some experimental codecs
-ar 44100 set the audio sample rate
-ac 2 specifies two channels of audio
-b:a 96k sets the audio bit rate
-vcodec libx264 sets the video codec
-r 25 set the frame rate
-b:v 500k set the video bit rate
-f flv says to deliver the output stream in an flv wrapper
'rtmp://<wowza server IP>/live/cam0' is where the transcoded video
stream gets pushed to
More information about the ffmpeg-user