How to create a WebM video file?
Solution 1:
You can use ffmpeg to convert to WebM. Make sure to compile it with the --enable-libvpx and --enable-libvorbis flags (see FFmpeg compile guides), or visit the FFmpeg Download page for links to builds that include support. After that, you can use the following command (I'm using input.flv as my example input file):
ffmpeg -i input.flv -vcodec libvpx -acodec libvorbis output.webm
For additional information, see the FFmpeg vpx (WebM) Encoding Guide.
Solution 2:
ffmpeg -i input.mp4 -c:v libvpx -crf 10 -b:v 1M -c:a libvorbis output.webm
By default the CRF value can be from 4–63, and 10 is a good starting point. Lower values mean better quality.
Solution 3:
I set this up recently, but it's kind of a pain. Here's what I had to do:
First, build ffmpeg from source to include the libvpx drivers (even if your using a version that has it, you need the newest ones (as of this month) to stream webm because they just did add the functionality to include global headers). I did this on an Ubuntu server and desktop, and this guide showed me how - instructions for other OSes can be found here.
Once you've gotten the appropriate version of ffmpeg/ffserver you can set them up for streaming, in my case this was done as follows.
On the video capture device:
ffmpeg -f video4linux2 -standard ntsc -i /dev/video0 http://<server_ip>:8090/0.ffm
- The "-f video4linux2 -standard ntsc -i /dev/video0" portion of that may change depending on your input source (mine is for a video capture card).
Relevant ffserver.conf excerpt:
Port 8090
#BindAddress <server_ip>
MaxHTTPConnections 2000
MAXClients 100
MaxBandwidth 1000000
CustomLog /var/log/ffserver
NoDaemon
<Feed 0.ffm>
File /tmp/0.ffm
FileMaxSize 5M
ACL allow <feeder_ip>
</Feed>
<Feed 0_webm.ffm>
File /tmp/0_webm.ffm
FileMaxSize 5M
ACL allow localhost
</Feed>
<Stream 0.mpg>
Feed 0.ffm
Format mpeg1video
NoAudio
VideoFrameRate 25
VideoBitRate 256
VideoSize cif
VideoBufferSize 40
VideoGopSize 12
</Stream>
<Stream 0.webm>
Feed 0_webm.ffm
Format webm
NoAudio
VideoCodec libvpx
VideoSize 320x240
VideoFrameRate 24
AVOptionVideo flags +global_header
AVOptionVideo cpu-used 0
AVOptionVideo qmin 1
AVOptionVideo qmax 31
AVOptionVideo quality good
PreRoll 0
StartSendOnKey
VideoBitRate 500K
</Stream>
<Stream index.html>
Format status
ACL allow <client_low_ip> <client_high_ip>
</Stream>
- Note this is configured for a server at feeder_ip to execute the aforementioned ffmpeg command, and for the server at server_ip so server to client_low_ip through client_high_ip while handling the mpeg to webm conversation on server_ip (continued below).
This ffmpeg command is executed on the machine previously referred to as server_ip (it handles the actual mpeg --> webm conversion and feeds it back into the ffserver on a different feed):
ffmpeg -i http://<server_ip>:8090/0.mpg -vcodec libvpx http://localhost:8090/0_webm.ffm
Once these have all been started up (first the ffserver, then the feeder_ip ffmpeg process then then the server_ip ffmpeg process) you should be able to access the live stream at http://:8090/0.webm and check the status at http://:8090/
Hope this helps.