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January 17, 2007

Flash streaming encoding settings - what are sites like YouTube doing? (and how can you find out?)

I'm trying to do something simple - find out the codec and bitrate information for Flash FLV videos found on the Web.  In RealPlayer, the "Statistics" menu option reveals everything you need to know, and shows even more if you launch it in "Debug" mode (holding the crtl-shift keys as you select 'Statistics" from the menu).  WindowsMedia provides similar info if you select "Properties" while it's playing. But Flash?  You're out of luck unless you do some extra work.  

My solution may not be the slickest one, but it's one I could work out in a few minutes of Googling around.  You need two things:
  1. First, a tool to download the FLV file to your local system so you can open it with a program that will expose the technical details you want.
  2. A program that analyzes the clip and outputs the codec and bitrate details of the file. 
Stumbling around, I found two options for downloading:
  • The Firefox extension Video Downloader.  This grabs embedded media from a page and saves it locally.  For video, it only works if the video is delivered via http download (not streaming). 
  • A Windows tool called WM Recorder 11.  This one hooks into your TCP/IP stack to automatically record any streaming content coming to your computer, including rtsp, mms, and rtmp streams. As a stream recorder, it's a very cool new option in addition to the old standby I wrote about in 2003, Cucusoft's StreamDown [buy].    
For examining the contents of a file, Moyea FLV Converter [buy] seems to be the best one of those I tried for extracting all the information from files encoded with both the H.263/Spark and On2 VP6 codecs. 

Some interesting findings?
  • YouTube, Metacafe, and Google are all doing Flash 7 - Sorenson Spark via http download.  Spark, based on H.263 isn't so great by today's standards, which explains why video on these sites often looks so bad. On the other hand it is compatible with Flash 7, making the installed base of players close to 100%.   It can also be encoded from a command-line (or from website code) using free or open-source tools like ffmpeg and Riva. Some video/audio bitrates I sampled are:
    • YouTube - 240kbps/64kbps
    • Google - 282kbps/64kbps
    • Metacafe - 330kbps/48kbps
  • Brightcove is rtmp streaming using the excellent Flash 8 VP6 codec, bitrates range from 308k/64k to 640k/96k.
  • Feedroom (responsible for video news sites like New York Times and USAToday is using rtmp streaming, but it's using another level of indirection in its site that makes its streams  not capturable by WMRecorder.

Disclosure: Some of the links above are affiliate links. Any of the pennies that trickle in from purchases of these products from these links will help support the ongoing costs of maintaining this site.

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i'd love to see how blip.tv compares. they allow you to download their flash videos, so you don't have to "rip" them out.

from wmrecorder.com,

"The following formats can't be recorded:
QuickTime RTSP
Flash Video RTMP

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