2 Replies Latest reply on Jul 29, 2010 8:13 AM by Colin Brougham

    Bloated FLV exports from Premiere/AME

    Colin Brougham Level 6

      I regularly export a 320x240 500kbps/96kbps mono VP6 FLV for one of my clients. With CS4, this would result in a decent-looking file that was a little bit over 2MB; the exact file weight would vary as I use 2-pass VBR, but they were still small. The muxed bitrate is about 600kbps--simple math, right?

       

      I just did an export by bringing my adding a PPro sequence directly to AME, and encoded using the setting above. The export didn't look as good as it usually does (MRQ and MBD were enabled), and the file is over 3MB! This is the MediaInfo report on the file:

       

      General
      Complete name                    : C:\Users\Public\Desktop\LRCR TV 8-10 Chevy.flv
      Format                           : Flash Video
      File size                        : 3.06 MiB
      Duration                         : 30s 40ms
      Overall bit rate                 : 853 Kbps
      
      Video
      Format                           : VP6
      Duration                         : 30s 40ms
      Bit rate                         : 500 Kbps
      Width                            : 320 pixels
      Height                           : 240 pixels
      Display aspect ratio             : 4:3
      Frame rate mode                  : Constant
      Frame rate                       : 29.970 fps
      Bits/(Pixel*Frame)               : 0.217
      Stream size                      : 1.79 MiB (59%)
      
      Audio
      Format                           : MPEG Audio
      Format version                   : Version 1
      Format profile                   : Layer 3
      Duration                         : 30s 40ms
      Bit rate mode                    : Constant
      Bit rate                         : 96.0 Kbps
      Channel(s)                       : 1 channel
      Sampling rate                    : 44.1 KHz
      Bit depth                        : 16 bits
      Stream size                      : 352 KiB (11%)
      

       

      The overall bitrate is reported as 853kbps, while the video bitrate is 500kbps and the audio bitrate is 96kbps. Granted, I don't use math too often these days, but that doesn't add up. The overall bitrate certainly accounts for the final file weight, but where is the bloat coming from? I just checked an H.264 export using similar settings, and the situation is the same: total bitrate is 744kbps (video and audio are same as above) and the file is larger than the component streams would indicate.

       

      I never had this issue with CS4 exports; what am I missing? Anyone else noticing the same?

        • 1. Re: Bloated FLV exports from Premiere/AME
          Colin Brougham Level 6

          OK, mystery partially solved, but this still isn't right. It appears that including the metadata in the exported file--even if there isn't much metadata included with the sequence--causes the bloat. But a full megabyte's worth? That seems extreme.

           

          Turning off the metadata inclusion helps somewhat, but the file is still larger than it should be. The video reports as 500kbps, the audio as 96kbps, but the total bitrate is 664kbps--that's not correct. I can export a smaller and better looking FLV (or MP4) from CS4 or from Squeeze, so what is CS5 doing to overstuff the export?

          • 2. Re: Bloated FLV exports from Premiere/AME
            Colin Brougham Level 6

            Did some more testing on this issue, this time with a 30-second DV clip. I thought maybe it was the sequence that was causing the bloat, but an export directly from a raw clip yields the same issue. I've tried exporting six ways from Sunday: from a sequence or from the Source Monitor, using either direct Export button or sending to the AME Queue, by adding it directly to AME, with metadata embedded and with it turned off. No matter what, the streams are reporting the correct bitrate, but the final muxed bitrate is far higher than it should be; I also tried encoding at a higher bitrate, and the same bloat occurs.

             

            Can anyone take a few moments and confirm this behavior? MediaInfo using the Tree or Text view will show the stream sizes and their percentage to the total weight of the file. Also, I've done a little testing with H.264 exports, and the issue does not seem to affect raw clips. Sequences exported to H.264 are a different story, though--some degree of bloat happens there. It would appear that the streams are encoded correctly, but my guess is that somewhere in the muxing process, a bunch of extra padding is being thrown in there.

             

            If this is a bug, would this be reported as a Premiere bug or an AME bug?