Update (Aug 15, 2008): The AMF0Parser library has been updated to support the Date type in the metas, added among others by the “inlet media FLVTool2″ tool.

If you’ve done Flash banners or micro-sites that embed video with cue points for synchronization before, you know that it’s a pain in the arse. There doesn’t seem to be any tool around to modify the damn points once the file is encoded, so you’ve got to re-encode the file over and over to have your things synced correctly.

If you’ve tried to reverse engineer the FLV format before, you know that it’s a pain in the arse as well. The AMF0 format is anything but intuitive, and the documentation has been lacking for a long long time — although there’s apparently an SDK now. Luckily, there was OSFlash, and SabreAMF and AMFPHP that could be used as a documentation source.

If you recognize yourself, this might be your lucky day. After many hours of trial and error, I’ve finally been able to reverse engineer it, and to build a library that extract essential FLV information, reads the Meta, and allows you to write them back — including the cue points.

First, you’ll need to FLVInfo2 and the AMF0Parser libraries, below. The FLVInfo2 library has three main functions:

• getInfo, which returns information gotten from analyzing the FLV file and it’s meta. Frame rate, bit rate, audio/video codec, width, height, etc.

  (
      [signature] => 1
      [hasVideo] => 1
      [hasAudio] => 1
      [minimalFlashVersion] => 8
      [video] => stdClass Object
          (
              [codec] => 4
              [width] => 320
              [height] => 240
              [keyframeRatio] => 0.0180537208278
              [keyframeEvery] => 55.3902439024
              [fps] => 15
              [bitrate] => 448
              [codecStr] => On2 VP6
          )
  
      [audio] => stdClass Object
          (
              [codec] => 2
              [frequency] => 22
              [depth] => 16
              [channels] => 2
              [bitrate] => 48
              [codecStr] => MP3
          )
  )

• getMeta, which returns the meta data, and the cue points

  Array
  (
      [metas] => Array
          (
              [0] => Array
                  (
                      [0] => onMetaData
                      [1] => Array
                          (
                              [duration] => 151.46
                              [width] => 320
                              [height] => 240
                              [videodatarate] => 500
                              [canSeekToEnd] => 1
                              [videocodecid] => 4
                              [audiodatarate] => 48
                              [audiocodecid] => 2
                              [framerate] => 15
                              [creationdate] => Tue Jun 17 13:06:15 2008
                              [Encoded_By] => orangetango Video Encoder
                              [Encoded_With] => orangetango Video Encoder
                              [metadatacreator] => orangetango FLV meta data writer
                          )
                  )
          )
      [cuepoints] => Array
          (
              [0] => Array
                  (
                      [0] => onCuePoint
                      [1] => Array
                          (
                              [name] => name1
                              [time] => 4.41
                              [type] => event
                          )
                  )
              [1] => Array
                  (
                      [0] => onCuePoint
                      [1] => Array
                          (
                              [name] => name1_end
                              [time] => 6.7
                              [type] => event
                          )
                  )
          )
  )

• rewriteMeta, which inputs an FLV file, meta data and cue points, and outputs a new FLV file.

As a practical example, you find the rewriteTagsForFile function in the example.php file, that rewrites the meta data and gets the cue points from a FLVCoreCuePoints XML file.

flvinfo2.php (175k)

AMF0Parser.php (96k, updated Aug 15, 2008)

example.php (12k)

Flash Video logo found on Wikipedia.

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