Help with MP4's please!
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mysteryboy
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mysteryboy
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Tahrey1043
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Sounds like you need a crash course in digital video. Try www.videohelp.com ... back when internets, MPGs and DivXs were my timewaste of choice (before first motors, then BLOODY WORK became order of the day) the site was an awesome resource.
That bitrate sounds awfully high to me for what you're using it for. Particularly too I would say, avoid the constant rate encoder setting, you're on a hiding to nothing with that - Variable bit rate (VBR) is where it's at, it's been around since MPG-1 and it's pretty much what MPG-2 and MPG-4 were built for (all pre-pressed DVDs use it, though most home DVD recorders don't, as it means you can't predict the remaining rec time).
Also if you can, source UK-format videos rather than US ones, as they'll only be 25.00fps instead of "30"fps, but will be crunched down to the same resolution (you won't notice the rate difference, particularly on an LCD). Also, if you do use US-spec vids, check first to see if they're 30 (29.97) or 24fps (23.976), as upping a 24 vid to 30 will not only waste space but make it hella jerky.
What resolution are you encoding at, by the way?
A little example in bitrate setting:
If your application uses the entire 480x272 PSP screen, and you're wanting to fit it in a 512mb memory stick, compare this to a typical DivX out of my collection: 640x352 (similar aspect ratio), in about 700mb, fitting a single CDR. Quality is still perfectly good for displaying full screen on a PC or TV (resolution is similar to DVD, and compression surprisingly not much more noticable as the routines are far cleverer).
For a typical 100 minute film, that's 7mb per minute, or,
7168kbyte/min
119kbyte/sec
955kbit/sec
and when you take away the sound (typically, MP3 at constant 128kbit, or VBR around this level), that leaves you with about an 827kbit/sec average target --- or half of what you're currently using.
This also is at 640x352, or 225kpix/frame. Yours will be a maximum of 480x272, that's 131kpix, or only 58% of that screen area ... theoretically you could get away with 480kbit/sec (nice round number!) and still have a watchable movie. Sticking with the 128kbit sound, that's a 608kbit total (call it 624 for reasons of file format overheads) = 78kbyte/sec, 4680kbyte/min, 4.57mb/min, or a grand total of 457mb for your 100 minute movie, easily fitting inside a typical "512mb" memory stick (often more like 480-490 "real" Mb) with some space spare for a few photos, mp3s, or what-have-you.
Playing with this depending on the resultant quality, and/or using a better audio compression format than MP3 (AAC, ogg, posssssibly ATRAC (105k) but please god not WMA) - or even plumping for mono - will free up bits to either give to the video stream, spend on extra minutes, or to just bring the size of the film down.
I've squashed 130 minute films (e.g. Fellowship of the Ring, Spirited Away) onto a single 800mb CD before in VCD format (352 wide by about 192 high, if letterboxed) using the archaic and inefficient MPG-1 format and they've come out fine, with some careful tweaks. Experiment with dropping your bitrate pretty hard - its not like you're going to break anything or have to pay money for each upload is it - and see what your personal quality tolerance level is.
(if you can track down the custom "kwag" vector quantisation matrix* and plug it into your encoder somehow, it really does seem to have a positive effect on compressed quality over the generic ones)
Good luck
* I SWEAR I'm not just making up words, there!
That bitrate sounds awfully high to me for what you're using it for. Particularly too I would say, avoid the constant rate encoder setting, you're on a hiding to nothing with that - Variable bit rate (VBR) is where it's at, it's been around since MPG-1 and it's pretty much what MPG-2 and MPG-4 were built for (all pre-pressed DVDs use it, though most home DVD recorders don't, as it means you can't predict the remaining rec time).
Also if you can, source UK-format videos rather than US ones, as they'll only be 25.00fps instead of "30"fps, but will be crunched down to the same resolution (you won't notice the rate difference, particularly on an LCD). Also, if you do use US-spec vids, check first to see if they're 30 (29.97) or 24fps (23.976), as upping a 24 vid to 30 will not only waste space but make it hella jerky.
What resolution are you encoding at, by the way?
A little example in bitrate setting:
If your application uses the entire 480x272 PSP screen, and you're wanting to fit it in a 512mb memory stick, compare this to a typical DivX out of my collection: 640x352 (similar aspect ratio), in about 700mb, fitting a single CDR. Quality is still perfectly good for displaying full screen on a PC or TV (resolution is similar to DVD, and compression surprisingly not much more noticable as the routines are far cleverer).
For a typical 100 minute film, that's 7mb per minute, or,
7168kbyte/min
119kbyte/sec
955kbit/sec
and when you take away the sound (typically, MP3 at constant 128kbit, or VBR around this level), that leaves you with about an 827kbit/sec average target --- or half of what you're currently using.
This also is at 640x352, or 225kpix/frame. Yours will be a maximum of 480x272, that's 131kpix, or only 58% of that screen area ... theoretically you could get away with 480kbit/sec (nice round number!) and still have a watchable movie. Sticking with the 128kbit sound, that's a 608kbit total (call it 624 for reasons of file format overheads) = 78kbyte/sec, 4680kbyte/min, 4.57mb/min, or a grand total of 457mb for your 100 minute movie, easily fitting inside a typical "512mb" memory stick (often more like 480-490 "real" Mb) with some space spare for a few photos, mp3s, or what-have-you.
Playing with this depending on the resultant quality, and/or using a better audio compression format than MP3 (AAC, ogg, posssssibly ATRAC (105k) but please god not WMA) - or even plumping for mono - will free up bits to either give to the video stream, spend on extra minutes, or to just bring the size of the film down.
I've squashed 130 minute films (e.g. Fellowship of the Ring, Spirited Away) onto a single 800mb CD before in VCD format (352 wide by about 192 high, if letterboxed) using the archaic and inefficient MPG-1 format and they've come out fine, with some careful tweaks. Experiment with dropping your bitrate pretty hard - its not like you're going to break anything or have to pay money for each upload is it - and see what your personal quality tolerance level is.
(if you can track down the custom "kwag" vector quantisation matrix* and plug it into your encoder somehow, it really does seem to have a positive effect on compressed quality over the generic ones)
Good luck
* I SWEAR I'm not just making up words, there!
Last edited by Tahrey1043 on Sun Feb 19, 2006 11:11 pm, edited 2 times in total.
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Tahrey1043
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just so long as it's of some use to you
i get enough stick for big data-dumps like that, worse when they're no good for anyone
Dunno why it gives you that high rate as a default (i assume this is the case?). Probably to cover all bases - e.g. if you use VBR, it adapts to the complexity of the video, if you set the average at 750 it might go up to 1500 on action scenes and bottom out way down at 150 or less with nearly-motionless sit-down dialogue. Almost any divx encoder you use should be smart enough to use 2-pass VBR encoding (it does a quick scan thru with a basic constant quality setup, and takes the predicted average rate from that as a yardstick for how to tweak the quality & fit it to what you've requested), or at least Constant Quality 1-pass (you have to manually set the level, and it just encodes it straight off - it's quicker, and it's possible to get a feel for what a suitable level is, but can require 5 or more passes when something catches you out). Only the real boggo ones have Constant Rate only ---- something that, admittedly, I certainly would not put past Sony, as their PC software packages typically ming like three month old chicken nuggets. See if you can find a third party encoder if that's the case.
1Gb gives you a bit more freedom to up the quality, but at this resolution and the compression level i'm talking about, it's the comfy middle ground - such that you can drop it a bit before it looks bad (if you need to just shave off those last 5mb), but you also have to add quite a bit of data rate before it goes from looking "very good" to "astonishing", and it's not really worth making them more than a half gig per full-length movie. You should be able to get a good number of TV episodes in that space. If the resolution is even more limited, or your standards are lower, you could even squeeze three typical films out of a gig.
(though i wouldn't reccomend the entirety of LOTR til you get a 2gb card - i've gone and squashed Spirited Away into an 8cm VCD before for a laff/experiment, and it was watchable but distinctly unpretty)
i get enough stick for big data-dumps like that, worse when they're no good for anyone
Dunno why it gives you that high rate as a default (i assume this is the case?). Probably to cover all bases - e.g. if you use VBR, it adapts to the complexity of the video, if you set the average at 750 it might go up to 1500 on action scenes and bottom out way down at 150 or less with nearly-motionless sit-down dialogue. Almost any divx encoder you use should be smart enough to use 2-pass VBR encoding (it does a quick scan thru with a basic constant quality setup, and takes the predicted average rate from that as a yardstick for how to tweak the quality & fit it to what you've requested), or at least Constant Quality 1-pass (you have to manually set the level, and it just encodes it straight off - it's quicker, and it's possible to get a feel for what a suitable level is, but can require 5 or more passes when something catches you out). Only the real boggo ones have Constant Rate only ---- something that, admittedly, I certainly would not put past Sony, as their PC software packages typically ming like three month old chicken nuggets. See if you can find a third party encoder if that's the case.
1Gb gives you a bit more freedom to up the quality, but at this resolution and the compression level i'm talking about, it's the comfy middle ground - such that you can drop it a bit before it looks bad (if you need to just shave off those last 5mb), but you also have to add quite a bit of data rate before it goes from looking "very good" to "astonishing", and it's not really worth making them more than a half gig per full-length movie. You should be able to get a good number of TV episodes in that space. If the resolution is even more limited, or your standards are lower, you could even squeeze three typical films out of a gig.
(though i wouldn't reccomend the entirety of LOTR til you get a 2gb card - i've gone and squashed Spirited Away into an 8cm VCD before for a laff/experiment, and it was watchable but distinctly unpretty)
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Tahrey1043
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can't say i'm familiar with any PSP software, not having one (or indeed much recent video software - all my versions are at least a year old, but hey... when i have cause to use 'em, they do the neccessary... i just need to find a freeware dual-layer DVD burner program 
)
i'll have a quick gander at the spec list at least though
edit (30 seconds later) - bingo, looks like they're just adding this functionality....
http://www.pspvideo9.com/forums/viewtopic.php?t=2334
I do find it wierd that it wasn't there from the get-go, however, because this sh*t is OLD news in DivX-land. If you can do a bit of independent research and find out if there's anything special about PSP files, or whether any old program can convert them given the right codec installation, that'd be bonzer. (Particularly if there's a way to trick it into playing back divx v3/4/5 or xvid files e.g. by changing the FourCC internal identity code - their encoders are excellent nowadays, and all self contained in the codec pretty much... the program you use just acts as an input/output, resize and filter shell)
though unfortunately apart from that, a general "features" list for the program is also sadly lacking. not a well written website that, despite the prettiness.
)i'll have a quick gander at the spec list at least though
edit (30 seconds later) - bingo, looks like they're just adding this functionality....
http://www.pspvideo9.com/forums/viewtopic.php?t=2334
I do find it wierd that it wasn't there from the get-go, however, because this sh*t is OLD news in DivX-land. If you can do a bit of independent research and find out if there's anything special about PSP files, or whether any old program can convert them given the right codec installation, that'd be bonzer. (Particularly if there's a way to trick it into playing back divx v3/4/5 or xvid files e.g. by changing the FourCC internal identity code - their encoders are excellent nowadays, and all self contained in the codec pretty much... the program you use just acts as an input/output, resize and filter shell)
though unfortunately apart from that, a general "features" list for the program is also sadly lacking. not a well written website that, despite the prettiness.
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Tahrey1043
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Ahem, sorry... a quick glossary, from the top down (sorry, it's lengthy again, but i'm trying laymanise it):
Dual layer burning software... i have a DVD drive that can do 8.5Gb discs (instead of the usual 4.7gb ones), some 8.5Gb blanks, but no program that can use them. Arses.
DivX 3/4/5 & Xvid files - types of windows .AVI that use the same MPG4 encoding method as I assume the PSP program does, just tweaked for a good long while (at least the last 4 or 5 years, as going thru my collection yesterday I found DivX 5 & Xvid CDROMs from mid 2003) to give uber quality and efficiency, and good speed.
Technically, they should all be fairly interchangable, as all the stuff they do, however clever, was all laid down in the original standard, they just encode it more smartly.
FourCC ID code - a thing in the file that identifies what flavour it is - Divx3, 4, 5, Xvid, ASF, WMV, MS MPG4, PSP, whatever. Normally best to leave it as-is just in case there's an odd extra feature been put in by one encoder the others can't figure out, but an old trick to force something to work with an otherwise incompatible player is to dick around with the code, thereby "disguising" the file. There's utils out there that can do this... I think I've only ever had to use it in anger the once, though.
And a less confused explanation of the VBR stuff:
1-pass / Constant quality: You tell it how hard you want to compress stuff, and it'll stick fairly close to that. The bitrate will vary with how complex the video image is from scene to scene (particularly, how much movement), and the output size is not fixed to the length. It's a reasonable method but not always the best, as it tends to over exaggerate how much data to throw at a scene, so still ones can lose quality and fast ones be far too hi-fi.
2-pass: It goes thru the file assessing it using an arbitary CQ encoding level, seeing which bits need how much data. No video data is stored, but the rate is. The encoder then does it CQ style properly, but using the guide, tweaks things both so that it more closely hits a target size, and so the over-exaggerations aren't so pronounced and everything's a lot more consistent.
Constant rate: Each frame gets the same amount of data, whether it's stock still or the most action filled bit of film you've ever seen. Therefore average scenes look generally ok, still bits are super-slick, and anything with moderately fast motion or complex images rapidly descends into the Blocky Horror Picture Show. And it usually uses more data than VBR. The three advantages are: faster encoding, much easier to estimate how much filespace a certain length of film needs, and the decoder can be simpler.
Dual layer burning software... i have a DVD drive that can do 8.5Gb discs (instead of the usual 4.7gb ones), some 8.5Gb blanks, but no program that can use them. Arses.
DivX 3/4/5 & Xvid files - types of windows .AVI that use the same MPG4 encoding method as I assume the PSP program does, just tweaked for a good long while (at least the last 4 or 5 years, as going thru my collection yesterday I found DivX 5 & Xvid CDROMs from mid 2003) to give uber quality and efficiency, and good speed.
Technically, they should all be fairly interchangable, as all the stuff they do, however clever, was all laid down in the original standard, they just encode it more smartly.
FourCC ID code - a thing in the file that identifies what flavour it is - Divx3, 4, 5, Xvid, ASF, WMV, MS MPG4, PSP, whatever. Normally best to leave it as-is just in case there's an odd extra feature been put in by one encoder the others can't figure out, but an old trick to force something to work with an otherwise incompatible player is to dick around with the code, thereby "disguising" the file. There's utils out there that can do this... I think I've only ever had to use it in anger the once, though.
And a less confused explanation of the VBR stuff:
1-pass / Constant quality: You tell it how hard you want to compress stuff, and it'll stick fairly close to that. The bitrate will vary with how complex the video image is from scene to scene (particularly, how much movement), and the output size is not fixed to the length. It's a reasonable method but not always the best, as it tends to over exaggerate how much data to throw at a scene, so still ones can lose quality and fast ones be far too hi-fi.
2-pass: It goes thru the file assessing it using an arbitary CQ encoding level, seeing which bits need how much data. No video data is stored, but the rate is. The encoder then does it CQ style properly, but using the guide, tweaks things both so that it more closely hits a target size, and so the over-exaggerations aren't so pronounced and everything's a lot more consistent.
Constant rate: Each frame gets the same amount of data, whether it's stock still or the most action filled bit of film you've ever seen. Therefore average scenes look generally ok, still bits are super-slick, and anything with moderately fast motion or complex images rapidly descends into the Blocky Horror Picture Show. And it usually uses more data than VBR. The three advantages are: faster encoding, much easier to estimate how much filespace a certain length of film needs, and the decoder can be simpler.
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Tahrey1043
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yeah...... ok...... thats very wierd. what length was the original file? going by your settings there should have been more than a 5x size difference between them all...
is this still using the sony software by any chance? (i'm suspecting it).
Could be it's padding them out to some standard size for some reason - it's a common thing to happen if you're encoding fixed-rate MPG-1 files or VBR ones for a player that's not happy with the very lowest rates (just fill the unused bits of each frame with zeroes, expanding the "control stream" part til the whole frame reaches a preset size....), but i don't see as it should happen for MPG-4s, even if you've fixed the rate.
is this still using the sony software by any chance? (i'm suspecting it).
Could be it's padding them out to some standard size for some reason - it's a common thing to happen if you're encoding fixed-rate MPG-1 files or VBR ones for a player that's not happy with the very lowest rates (just fill the unused bits of each frame with zeroes, expanding the "control stream" part til the whole frame reaches a preset size....), but i don't see as it should happen for MPG-4s, even if you've fixed the rate.