Quantcast FFmpeg: Bitrate Peaks - Page 2 - digitalFAQ.com Forums [Archives]
  #21  
02-29-2004, 08:13 PM
vhelp vhelp is offline
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@ kvcd,

Quote:
Maybe it's time for me to write "Bitrate Peeper"
And, make it command-line too
-vhelp
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  #22  
02-29-2004, 08:59 PM
kwag kwag is offline
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Quote:
Originally Posted by vhelp
And, make it command-line too
A command line bitrate viewer
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  #23  
02-29-2004, 09:12 PM
vhelp vhelp is offline
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Quote:
A command line bitrate viewer
NOOO!! goofy!!

I mean, if your tool was gonna give us a few numbers, it could be used in
other toolings or calculations, and we could incorporate it somehow
into our apps for strength

-vhelp
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  #24  
02-29-2004, 10:01 PM
kwag kwag is offline
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Quote:
Originally Posted by vhelp
Quote:
A command line bitrate viewer
NOOO!! goofy!!

I mean, if your tool was gonna give us a few numbers, it could be used in
other toolings or calculations, and we could incorporate it somehow
into our apps for strength

-vhelp
I was thinking on something similar to Bitrate Viewer, but with more visual statistics
Maybe a combination of Bitrate Viewer + DVDPatcher + VBVPatcher + MPEGanalizzatore + mpegprop
But then again, that would take some time to build, as the full MPEG bit stream pattern has to be decoded, organized and displayed. That would be a usefull application, and it would really be a true MPEG analyzer

-kwag
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  #25  
02-29-2004, 10:55 PM
poerschr poerschr is offline
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..about that DVD is was just talking about...It played perfectly, it tested it for two hours...definatly a problem with bitrate viewer...
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  #26  
03-01-2004, 04:47 AM
Hydeus Hydeus is offline
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There is already (beter to tell "will be") alternative to BV: MPEG Validator (information post on doom9), but there is no published code or binaries of this, for unknown reason
Is there someone able to answer my question about SVCD with DVD-VBV value
__________________
Go for SECAM =)
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  #27  
03-01-2004, 08:58 AM
marcellus marcellus is offline
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Quote:
Originally Posted by kwag
Quote:
Originally Posted by vhelp
Quote:
A command line bitrate viewer
NOOO!! goofy!!

I mean, if your tool was gonna give us a few numbers, it could be used in
other toolings or calculations, and we could incorporate it somehow
into our apps for strength

-vhelp
I was thinking on something similar to Bitrate Viewer, but with more visual statistics
Maybe a combination of Bitrate Viewer + DVDPatcher + VBVPatcher + MPEGanalizzatore + mpegprop
But then again, that would take some time to build, as the full MPEG bit stream pattern has to be decoded, organized and displayed. That would be a usefull application, and it would really be a true MPEG analyzer

-kwag
Wishfull thinking:
A way to get rid of bitrate peaks could be an automated process like the following:
analyze m2v stream and find the over-standard spots -> break the stream at the nearest I frames -> run rejig on the over-bitrate segements -> splice all the segments back
marcellus
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  #28  
03-01-2004, 09:14 AM
kwag kwag is offline
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Quote:
Originally Posted by marcellus
Wishfull thinking:
A way to get rid of bitrate peaks could be an automated process like the following:
analyze m2v stream and find the over-standard spots -> break the stream at the nearest I frames -> run rejig on the over-bitrate segements -> splice all the segments back
marcellus
Actually, a simpler way (based on your thought ) would be to modify ReJig so instead of recompressing frames with a %, to actually "trim" frame bitrate that are above a treshold.
This way, we can just set a MAX bitrate, and anything that is >= to that bitrate, is re-encoded with that MAX bitrate.
I think this would be a simple modification to ReJig.
Then, we can call it ReClamp

-kwag
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  #29  
03-01-2004, 09:33 AM
digitall.doc digitall.doc is offline
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And with this aproximation, Kwag, will quality suffer?.
I mean, after reencoding with Rejig (or it doesn't really reencode?), and lowering bitrate without adjusting Q, won't these scenes suffer of lack of bitrate?.
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  #30  
03-01-2004, 10:14 AM
kwag kwag is offline
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Quote:
Originally Posted by digitall.doc
And with this aproximation, Kwag, will quality suffer?.
I mean, after reencoding with Rejig (or it doesn't really reencode?), and lowering bitrate without adjusting Q, won't these scenes suffer of lack of bitrate?.
Yes it will suffer, but if they are quick "spikes', for example on a single I frame, then you probably won't notice it when playing it on the TV.
Only if you were to slow motion, then you would see some frames with blocks.
This would have to be tested

-kwag
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  #31  
03-01-2004, 10:22 AM
digitall.doc digitall.doc is offline
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Quote:
Originally Posted by kwag
Only if you were to slow motion, then you would see some frames with blocks.
This would have to be tested

-kwag
Yes kwag, this is my problem now: doing so many tests that most of them I see with my nose stuck to the monitor to look for artifacts-macroblocks, and many scenes in low motion...
But this is not the way we will see them later, isn't it
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  #32  
03-01-2004, 10:34 AM
poerschr poerschr is offline
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I dont know...I am not convinced that their is any program with the VBV...all of the streams that I have made have played perfectly....I think the program is where Bitrate viewer establishes the baseline...something in ffvfw conflicts with Biterate viewer or has a difficult time establishing a true baseline...this must be related to the VBV issue....
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  #33  
03-01-2004, 11:01 AM
marcellus marcellus is offline
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Quote:
Originally Posted by kwag
Quote:
Originally Posted by digitall.doc
And with this aproximation, Kwag, will quality suffer?.
I mean, after reencoding with Rejig (or it doesn't really reencode?), and lowering bitrate without adjusting Q, won't these scenes suffer of lack of bitrate?.
Yes it will suffer, but if they are quick "spikes', for example on a single I frame, then you probably won't notice it when playing it on the TV.
Only if you were to slow motion, then you would see some frames with blocks.
This would have to be tested

-kwag
I'm also thinking that is unlikely to see any artifacts because the target bitrate (after rejig) should be the maximum permited by the standard, meaning a big enough bitrate to alow artifacts to be seen.
marcellus
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  #34  
03-01-2004, 11:04 AM
bilu bilu is offline
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Quote:
Originally Posted by kwag
Quote:
Originally Posted by marcellus
Wishfull thinking:
A way to get rid of bitrate peaks could be an automated process like the following:
analyze m2v stream and find the over-standard spots -> break the stream at the nearest I frames -> run rejig on the over-bitrate segements -> splice all the segments back
marcellus
Actually, a simpler way (based on your thought ) would be to modify ReJig so instead of recompressing frames with a %, to actually "trim" frame bitrate that are above a treshold.
This way, we can just set a MAX bitrate, and anything that is >= to that bitrate, is re-encoded with that MAX bitrate.
I think this would be a simple modification to ReJig.
Then, we can call it ReClamp

-kwag
Hey, you're steeling my idea!

From my first post ever on this forum...
Posted: Wed Jan 28, 2004 12:21 pm

http://www.kvcd.net/forum/viewtopic.php?t=8835

Quote:
I'd like to know if anyone has tried FFMPEG MPEG-2 encoding under FreeBSD, if there are any new developments on the max bitrate problem, and if there is any way to use a requantizer tool like M2VRequantizer to post-process the FFMPEG output that overlaps max bitrate.
Bilu
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  #35  
03-01-2004, 11:26 AM
kwag kwag is offline
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Quote:
Originally Posted by marcellus
I'm also thinking that is unlikely to see any artifacts because the target bitrate (after rejig) should be the maximum permited by the standard, meaning a big enough bitrate to alow artifacts to be seen.
marcellus
If ReJig does set a MAX bitrate constraint, and restricts it to the DVD standard, then running ReJig as it is set to 100%, would do the trick
It would basically "clip" the MAX bitrate, and make it standard. Worth a try

-kwag
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  #36  
03-01-2004, 11:32 AM
marcellus marcellus is offline
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Quote:
Originally Posted by bilu
Hey, you're steeling my idea!
WOW, sorry, I surely missed your post!
marcellus
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  #37  
03-01-2004, 11:33 AM
kwag kwag is offline
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Quote:
Originally Posted by bilu
Hey, you're steeling my idea!

From my first post ever on this forum...
Posted: Wed Jan 28, 2004 12:21 pm

http://www.kvcd.net/forum/viewtopic.php?t=8835

Quote:
I'd like to know if anyone has tried FFMPEG MPEG-2 encoding under FreeBSD, if there are any new developments on the max bitrate problem, and if there is any way to use a requantizer tool like M2VRequantizer to post-process the FFMPEG output that overlaps max bitrate.
Bilu
Actually it's not the same thing
The way ReJig works, is that it recompresses frames in order to achieve a destination size.
What I proposed, is a modification to ReJig, so it "clips" high bitrate peaks only.
So it's not the same

-kwag
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  #38  
03-01-2004, 12:17 PM
kwag kwag is offline
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Well, just made the test with ReJig at 100% (no compression). It didn't work
I encoded a small clip with ffvfw (anamorphic 720x480) which peaked at 10,553Kbps, and after processing with ReJig, the peak is still 10,553Kbps.
So ReJig doesn't clip MAX bitrate to DVD standard.

-kwag
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  #39  
03-01-2004, 12:27 PM
marcellus marcellus is offline
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Quote:
Originally Posted by kwag
Well, just made the test with ReJig at 100% (no compression). It didn't work
Probably at 100% rejig simply does nothing. In my algorithm I thought that at every spot with over-standard bitrate, before rejig, it must be figured out a percent for rejig to do his task. Besides, I don't think rejig incorporates the code to analyze the bitrate at every frame, it simply requanitzes the entire stream by a coeficient obtained from actual bitrate/target bitrate ratio. The analysis must be made outside rejig
marcellus
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  #40  
03-01-2004, 01:10 PM
bilu bilu is offline
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Quote:
Originally Posted by kwag
Actually it's not the same thing
The way ReJig works, is that it recompresses frames in order to achieve a destination size.
What I proposed, is a modification to ReJig, so it "clips" high bitrate peaks only.
So it's not the same

-kwag
But it is!!!

Rejig is based on M2VRequantizer, and I was looking for " any way to use a requantizer tool like M2VRequantizer to post-process the FFMPEG output that overlaps max bitrate."

I was referring to "requantize when needed". To requantize the whole thing was an already known process

Bilu
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