You can easily extract video metadata into a hash with mplayer and Ruby:
1 class Metadata 2 3 def self.get(file) 4 command = "mplayer -vo null -ao null -frames 0 -identify #{file}" 5 metadata = nil 6 7 Open3.popen3(command) do |input, output, error| 8 metadata = output.readlines.grep(/ID_.*/).collect {|name| name[3..name.length].split('=')} 9 metadata = metadata.inject({}) {|hash, (key, value)| hash[key.to_sym] = value.chomp; hash} 10 end 11 12 return metadata 13 end 14 15 end
Then in an RSpec test do:
1 it "should support 3gp" do 2 metadata = Metadata.get("videos/sony_ericsson_k850i.3gp") 3 4 metadata[:DEMUXER].should == 'mov' 5 metadata[:VIDEO_FORMAT].should == 's263' 6 metadata[:VIDEO_WIDTH].should == '176' 7 metadata[:VIDEO_HEIGHT].should == '144' 8 end
Note to self: metadata.demuxer would perhaps be a slightly better syntax.
This is a short tutorial on how to quickly get up to speed with FLV movie creation (transcoding) and viewing (Flash player).
I tried to install ffmpeg using ports and fink, but had problems. The instructions I found here work though.
The following is my adaptation of the instruction, where I show you how to install both ffmpeg and flvtool2.
First, download ffmpegx, which contains ffmpeg from http://ffmpegx.com/download.html
Then, mount the .dmg file, navigate to the mounted disk, and control-click on the ffmpegX application (ffmpegX.app), choose Show Package Contents from the pop-up menu, and copy the ffmpeg binary to, for example, /tmp.
Now execute the following commands in a terminal shell:
1 # Move ffmpeg to /usr/local/bin: 2 sudo mv /tmp/ffmpeg /usr/local/bin/ 3 4 # Change owner and make executable 5 sudo chown root:wheel /usr/local/bin/ffmpeg 6 sudo chmod 755 /usr/local/bin/ffmpeg
You’re now ready to use ffmpeg; the following command lists all the supported input and output formats:
1 ffmpeg -formats
Use the following command to transcode an AVI to FLV (Flash video) format:
1 fmpeg -i mymovie.avi -s 320x240 -ar 44100 -r 12 mymovie.flv 2 cat mymovie.flv | flvtool2 -U stdin mymovie.flv
To add metadata to the FLV file—such as video length, which is required for the Flash player progress bar—you need to install flvtool2.
This is done with the following command (note this requires Ruby and RubyGems, which are not part of all OSX Leopard installations):
1 sudo gem install flvtool2
Now add the metadata to the FLV file:
1 flvtool2 -UP mymovie.flv
To test the FLV movie you just created, download and extract FlowPlayer to your folder of choice. Now create a page that loads your FLV movie; note that you need to update the paths:
1 <html> 2 <head> 3 <script type="text/javascript" src="../flowplayer/html/swfobject.js"></script> 4 </head> 5 <body> 6 <div id="flowplayerholder"> 7 This will be replaced by the player. 8 </div> 9 10 <script type="text/javascript"> 11 // <![CDATA[ 12 var fo = new SWFObject("../flowplayer/FlowPlayerDark.swf", "FlowPlayer", "468", "350", "7", "#000000", true); 13 // need this next line for local testing, it's optional if your swf is on the same domain as your html page 14 fo.addParam("allowScriptAccess", "always"); 15 fo.addVariable("config", "{ countryCode: 'fi', playList: [ {overlayId: 'play' }, { url: '/mockup/mymovie.flv' } ], initialScale: 'scale', fullScreenScriptURL: 'fullscreen.js' }"); 16 fo.write("flowplayerholder"); 17 // ]]> 18 </script> 19 </body> 20 </html>
I’ve been told that mencoder produces higher quality FLV videos, so lets compare the mencoder output to ffmpeg by first downloading and extracting mencoder to /tmp.
Now move mencoder to /usr/local/bin:
1 sudo mv /tmp/mencoder /usr/local/bin/ 2 3 sudo chown root:wheel /usr/local/bin/mencoder 4 sudo chmod 755 /usr/local/bin/mencoder
Next transcode the video to FLV format using mencoder:
1 mencoder mymovie.avi -ofps 12 -o mymovie.flv -of lavf -lavfopts \ 2 i_certify_that_my_video_stream_does_not_use_b_frames -oac lavc -lavcopts \ 3 acodec=mp3:abitrate=32 -srate 22050 -ovc lavc -lavcopts vcodec=flv:\ 4 vbitrate=100:mbd=2:mv0:trell:v4mv:cbp:last_pred=3:predia=2:dia=2:\ 5 vmax_b_frames=0:vb_strategy=1:precmp=2:cmp=2:subcmp=2:preme=2:qns=2 \ 6 -vop scale=360:240
View the video in the Flash player; you should notice the difference in quality…
For even higher quality encode the videos using the H.264 format, which FlowPlayer also supports; instructions can be found here.
By default an flv movie doesn’t contain the duration metadata. Using the flvtool2 program it is injected like this into the movie file.
1 cat mymovie.flv | flvtool2 -U stdin mymovie.flv
Create an flv movie that is 320 wide by 240 high. For audio functionality ffmpeg needs to be compiled with the following parameters:
1 --enable-amr_nb 2 --enable-amr_nb-fixed 3 --enable-amr_wb 4 --enable-mp3lame
The snippet itself:
1 ffmpeg -i mymovie.avi -s 320x240 -ar 44100 -r 12 mymovie.flv