• Adobe After Effects

  A problem with AE 7 and output bit rates

  Posted by John Clark on March 19, 2006 at 2:46 am

  When I render, and select Mpeg-4 output, select a ‘bit rate limit’, the resulting movie does not seem to ‘honor’ the selected bit rate. When I then use QT-Pro to export a new movie, with the desired bit rate,
  there are some strange phenomena as well, but the bit rate is at least lower or at my selected value.

  Have others had this sort of problem?

  Thanks
  John Clark

  Roland R. kahlenberg replied 20 years, 4 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Roland R. kahlenberg

  March 19, 2006 at 6:51 pm

  Different applications handle the bitrate setting differently. With certain software, this could be an average bitrate and with others, it could be a maximum. And then there’s the case where different CODECs and compression methods (VBR or CBR, single or two-pass) will hinder the options avaialable to you.

  I haven’t tested version 7 for compression so I can’t give you any first-hand information.

  If you need to do a bit of compression work then look for a solid compression software to do the job for you.

  RoRK
  broadcastGEMs
  customizable animated backdrops with Adobe After Effects project files
• 

  John Clark

  March 20, 2006 at 2:37 pm

  This problem I see is not related to ‘different’ applications and how they may encode. It has to do with the presented options, using ‘quciktime’ as the underlying output function. In the Format dialog under the rending setup options, one can select ‘quicktime’ encoding options.

  I select ‘limit bitrate’ to 6400 Kbs. When I then run the resulting quicktime movie, the quicktime movie info window has ‘anything but’ 6400, usually much more.

  I then use quicktime pro to select the options, using the same ‘encoding’ as what I had selected via AE, and the resulting output does have at least under the limited data I’ve indicated.

  This seems to me to be either a ‘problem’ with AE communicating the selected options to the quicktime compressor, or some option in AE that I’ve not enabled correctly.
• 

  Roland R. kahlenberg

  March 20, 2006 at 3:40 pm

  As you have just mentioned, AE does encode differently from QTPro in this specific instance. I suggest that you get in touch with the AE development team to see if they can fix this in a future release. For now, at least you have QTPro to do the work for you.

  You should try to understand that most CODECs come with a bunch of parameters that can be controlled by the software performing the encoding. If you look at a more advanced encoding option such Squeeze, you will notice that they have 2-pass variable bit rate encoding. This is not avaiable in AE. However, the Sorenson 3 CODEC does offer this feature. It is up to developers to implement the features they want for their users. Off course, equally important is for the parameter settings to work as they should.

  In this instance, I believe that AE’s rendering engine is deficient.

  Cheers
  RoRK

  broadcastGEMs
  customizable animated backdrops with Adobe After Effects project files

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