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Maximising BITRATE

mrj03 posted 2003 Mar 05 13:51
Im doing some experimenting with the BITRATE #'s
seeing how high I can crank them up to get the BEST
picture quality possible. I thought if I raised the Max. /
Max. avg it would allocate HIGHER bitrates to the action
scenes therefore having a HIGHER avg. Bitrate. When I did
the first test the AVG.BITRATE was EXACTLY the same as
when I used the DEFAULT Bitrate setting. What do I need to
change to accomplish a HIGHER AVG. BITRATE??

DEFAULT SETTING:
Min. bitrate: 300
Max. bitrate: 2530
Avg. Bitrate: 1961

TEST SETTING:
Min. bitrate: 300
Max. bitrate: 3500
Avg. Bitrate: 1961

THANKS....



hwoodwar posted 2003 Mar 05 15:31
The first thing I would look at that may cause you to not see much of a difference, would be the capture bitrate, or the bitrate that the original file uses. I capture off of cable a lot, and make note of the captured (labeled as Data Rate in VirtualDub) bitrate and do not make my max bitrate any higher than that is, as it would be a waste of space. If your capture bitrate was close to 2530kbps than this could account for the fact that you are seeing little difference between the two.

Another thing I can think of that may account for both seemingly close to the same quality would be the size of the monitor you are doing the comparison, on. I find it hard if not impossible, sometimes to see scenes with macroblocks in them on my 17 inch computer monitor. yet, when I play that same scene on my 27 inch TV I can easily see macroblocks that I could not see on the 17 inch monitor. Try to make the comparison on the largest monitor/TV you have available. You may indeed see a more significant difference.

Lastly (this is just a guess) if you lower the average bitrate, although the average quality of the entire video, may suffer, this may actually allow for more bitrate to be used where it is needed with the action-scenes and then you may see more of a difference with those action-scenes.



jagabo posted 2009 Oct 27 09:52
Also keep in mind that for all the shots that get higher bitrates there must be other shots that get lower bitrates.


tomlee59 posted 2009 Oct 28 19:22
You didn't say anything about the source. But if the encoder is able to encode all the high motion/high detail parts with the default maximum, then it would not need the extra bits. For VCDs, the bitrates you've shown are pretty high.

Now, if you want to stress-test the encoder, crank up the resolution. You will quickly find the bitrate saturating at the limits you set.



MOVIEGEEK posted 2009 Oct 28 21:14
Talk about resurrecting a dead thread(3/5/03).







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