Need help increasing filesize of mpeg via CBR in MSP 7 w/sp3

Uhfgood
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Need help increasing filesize of mpeg via CBR in MSP 7 w/sp3

Post by Uhfgood »

I used Pinnacle studio 11 to capture 2 1-hour videos in MPEG2 (using about 10k bit rate -- ie the highest it would capture at. ) I like to use MSP to combine the two into a watchable dvd, that fits on a 4 gig dvd-r. I found out I like using CBR rather than VBR (Please no questions about why I use Constant verses variable).

My problem here is, when I increase the bitrate the filesize of the resulting 2-hour mpeg does not seem to change. I've tried 4000, 5120, and 6144 -- the filesize tops out about 3.8gig. I just wanted to keep increasing the bitrate until it tops out anywhere from 4.3-4.7 (obviously not past dvd-r size). I can't seem to get it to change no matter what I try. Tonight I might try 8000 for my bitrate just to see if it does anything to it.

The only thing that seemed to affect file size is when I switched from 44.1k for audio to 48k, it jumped from 3.6 gig to 3.8 but other than the sound the filesize doesn't seem to change. I have the quality slider all the way up to 100, so maybe this has something to do with it.

Any idea of how I can get it to increase the bitrate?

Also for some reason I can't really seem to get info about the resulting file, but according to videolan (vlc) player, it's running somewhere around 4400 kbps -- although this seems to change a bit.

Edit:
I ran this file through GSpot and it claims that it's a 4534kb/s VBR -- even though I explicitly chose CBR in MSP

Thank you.
Keith Weatherby II
Uhfgood -at- Verizon -dot- net
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Post by sjj1805 »

2 x 1 hour videos at 10K would not fit on a single layer DVD, the most you should get is 1 hour at 8000 kbps.

Why are you capturing in MPEG2 in the first place?
If you are looking for best quality - as suggested by your CBR and 10K comments then you should be capturing in DV and only converting to MPEG2 after editing.

A guide to the correct bit rate settings is here:
What Bit Rate Settings etc Should I use?
Uhfgood
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Post by Uhfgood »

Sorry, I didn't explain it well.

I captured originally in mpeg2 because my hard drive space was at a premium, and because pinnacle studio and my computer can do it in realtime without dropping frames. I had cranked the bitrate as far as it would allow, to eventually be converted into something smaller. (a viewable version that would fit on 1 dvd-r by compressing it).

So I took the two 1 hour mpegs, and put them together in video editor. (They are two hours from the same hi-8 videotape). I wanted MSP to create a single 2 hour mpeg. I chose constant bit rate for my resultant file, and started about 4000. I noticed the file size was a gig less than the full space on a dvd-r. So I tried to increase the bitrate, all the way up to 6144 just to see if the file size would change. But it's never gotten over 3.8gig. I'm not sure why. When I analyzed it with g-spot it said it was at variable bit rate about 4500.

So first the file didn't get created with constant bitrate, and second it never changed it's bit rate no matter what number I put in there.

I'm wondering what I'm doing wrong, how come MSP won't encode it at constant bit rate and change file size when I increase the bitrate.

I'm using MSP 7 with service pack 3 installed.
Devil
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Post by Devil »

BIG error! If you MUST capture in MPEG-2 (which is not recommended), then do NOT capture with a high bitrate; capture it at your estimated distribution bitrate.

If you capture at a high bitrate, you have to totally re-encode everything which means quality loss. If you capture at ~4500 kbit/s CBR (whatever fits), then, with SmartRender, only the bits you have altered will be re-encoded with a quality loss, while the unaltered parts will not be re-encoded, so will keep your original quality.

You do not mention audio type and bitrate. This can have a profound influence, as LPCM can add over 1500 kbit/s to your bitrate.

Why don't you capture in MSP? It is always risky to change horses in midstream as small changes in the header bit settings cannot necessarily be used to advantage in other applications.

Then, you seem to be confused about what a DVD will hold. The ideal file size is about 4.0 Gb, 4.1 Gb at the outside. 4.37 Gb is the theoretical max, but the experience of many seasoned users is that pushing it towards the limit is very risky, unless you need some new coasters or bird scarers. 3.8 Gb is not bad, at all.

CBR is NEVER constant. Quantisation changes will cause the bitrate to fluctuate, albeit within narrow limits: I don't know the exact tolerance, but it's possibly within ¡Ó5%. Do not worry if a bitrate reader shows it is not absolutely constant, although a header bit should be set, telling the reader it is CBR. This could be a problem with different marques of software.

My advice:
1. capture in MSP
2. preferably capture in a proper capture format, not a distribution format like MPEG
3. if you must capture in MPEG, do so at your final CBR bitrate, not at a bitrate that is incompatible with DVDs. I agree with you VBR can be tricky and lower quality for no purpose.
4. carefully choose your audio system/bitrate
5. make sure you have plenty of HDD space available: burning SD can require up to 12 Gb or more of HDD, depending on your settings.
6. AT THE TOP OF THE BOARD, YOU WILL SEE A THREAD THAT IS LABELLED "Announcement: PLEASE READ THIS FIRST BEFORE POSTING!!! (modified)" Believe it or not, this applies to you, as well: please read it AND COMPLY with the instructions.
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Uhfgood
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Post by Uhfgood »

Sorry if I missed something, but I have read it.

Capturing in mpeg 2 wasn't a mistake for me, since I don't have that much disk space to begin with, and it doesn't drop frames.

I don't actually capture in MSP because for some reason it was not picking up the audio.

I'm capturing at the highest bit rate possible, to have the highest quality within the mpeg 2.

I'm saving my home movies, I don't care if I have to recompress to get it to fit on a single 4 gig dvd-r.

All I am trying to do is to create another mpeg 2 video, using CBR, and putting it different bitrates to see the largest filesize I can get without going over the limit. (As I've said, i've tried 4000, 4500, 5120, 6144)

As far as the audio goes, I believe it's just mpeg audio at 48k, a bit rate of something like 224 or 256 (whatever the default was set to, since it sounded ok I didn't see a need to mess with it).

I've done this before, in this exact same piece of software (only running in windows 2000), however I can't for the life of me, figure out why changing the bit rate doesn't result in different file sizes, and why the resultant file isn't being reported as CBR.

Can MSP convert a VBR mpeg 2 file into a CBR file? (Maybe this is where my problem is).

Please don't try to tell me that I must capture and do things this way or that way, I am simply trying to get the software to make any changes one way or another, and it's simply not doing for reasons I cannot understand.

I really don't understand why, when someone asks a question that instead of getting an answer like "Oh it can't do that" or "you're setting such and such wrong", you get an answer such as "Why are you doing it that way" "You should do it like this" blah blah blah.

If you don't want to answer that's alright with me, but please don't try to give me an answer that I did not ask for.

Again simply, i'm trying to create a 2 hour mpeg 2 file, using CBR at several different bitrates (to see the changes), out of 2 1-hour Variable bitrate mpeg 2 videos, using msp and the video editor. But when I change the bitrate the file stays the exact same size, and i'm just trying to understand why.

Just to make sure that I didn't miss something this time I re-read it.

Currently my specs are Asus M2N-SLI deluxe motherboard, with an amd phenom quad core 9500 cpu, 2 gigs of 6400 (800mhz) dual channel ram (ie 2 1-gig strips arranged for dual channel), it has on board sound. I have an nividia geforce 8600 GT, with Pinnacle Studio 11 plus (includes a pci card and breakout box).

I captured my video in two 1 hour segments with the studio 11 software (like i said msp wasn't picking up the audio for some strange reason). I tried to use the highest bit rate using mpeg 2 capture (as these are home movies and my hard drive space is low). It's something like around 10k -- yes i realize that's higher than most even double layer dvd's go. I'm going to be saving the mpeg's on dvd as regular data (the captured 1 hour videos). I'm going to make a watchable one by putting the two halves together and compressing it. I don't care how bad it is to compress down to 4 gig. Yes I realize 3.8 is respectable, and the file doesn't look half bad, but this still doesn't tell me why I can't change the bit rate and have it affect the resultant file at all.

If this is too much to ask for an answer to, I guess I won't post in here anymore. Since MSP is on the way out anyway, I guess I shouldn't be worried about it.
GeorgeW
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Post by GeorgeW »

When you originally re-encoded the file -- did it take alot longer than the subsequent encodes (i.e. the first file that resulted in 3.8gb took "x" minutes, and the subsequent tries to raise the bitrate took "y" minutes). Do you recall if there was a huge difference in "x" vs "y" times?

I suspect that MSP is re-using the original 3.8gb encode. To prevent that, when you render again, try unchecking the "Smartrender" checkbox -- to force it to re-encode at your new settings. Also, when you re-render, try to re-render from the originally captured files (as that will preserve the best quality from the original captures).

Regards,
George
Uhfgood
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Thank you!

Post by Uhfgood »

Thanks GeorgeW for answering the question directly. I didn't encode it from the resultant file. I did re-encode it from the original captures. I will try to uncheck the smartrender and tell you how that goes.

Thanks again for answering (even if it doesn't work, although it should).

I found the option and it's working, I will tell you how the file turns out.

Keith
Uhfgood
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Post by Uhfgood »

Okay I turned off smart render, and for some reason, the file size is STILL THE SAME. I don't understand, a bit rate of 6144 should yield about a 5 or more gig file. Smart render is off, and yet it's still at around 3.8 gig. (Actually I simplified it to 3.8 it's probably more like 3.6 or something, as it's 3,829,553).

But the file size didn't change. I'll try 8000 for the bitrate but I don't have any hopes for it.

Could someone tell me please, if there are some extra files msp (7) stores for smart rendering?
troppo
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Post by troppo »

Just another answer to a question you didn't ask:
If disk space is at a premium why not encode to a more efficient (and newer) format like h.264?
http://www.broomevideo.com
Uhfgood
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Post by Uhfgood »

Does h.264 encode into a dvd? How big are the file sizes compared to mpeg 2? Can I get a free implementation? I thought mostly quicktime used h.264?

As you can see I know nothing about it, which is probably why I'm not encoding in that.
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Post by Devil »

As you still have not filled in your details, as requested, I am at a loss to understand why, if you have a reasonably powerful computer, why you are so short of disk space. Can't you add another internal drive (SATA or ATA), reserved for video? You can buy a, say, 200 Gb drive for almost next to nothing and that would allow you to put on 10 hours of DV plus 10 hours of quality DVD files.

Before you jump down my throat again, no one has been telling you what to do, they have been giving you advice as to how best to do what you want as the final result. There is a world of difference. And PLEASE read that BEFORE YOU POST thread yet again and take note of what it says and act accordingly. It is there to help you give the info we need to advise you.
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Uhfgood
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Post by Uhfgood »

No money for another internal hd at the moment.

I believe i have filled in my details, but for completeness I will go over them again.

Asus m2n-sli deluxe mobo.
AMD phenom 9500 quad core cpu (2.2 ghz)
2 gig of 6400 ram (800mhz) configured as dual channel
60 gb hard drive space (well because i'm using it more like 45)
on board sound.
I'm running windows xp home with service pack 2

I'm using Media studio pro 7, with service pack 3.

Original captures: two one hour mpeg 2 captures from one source tape
10k for the bit rate, VBR, 720x480 interlaced, Mpeg audio at 48khz and 256kbps. The reason I'm using mpeg to capture my home movies (these are no professional) is because I don't have much disk space, so using a lower compression or lossless codec is not going to give me much room. Also I captured two 1-hour videos instead of 1 2-hour video is so I can fit each hour onto a separate dvd-r for archive purposes (just home movies understand). I'm using the 10k for the bitrate because that's as high as my capture board would go. I'm using Pinnacle Studio 11 plus (pci) to capture my video.

I'm trying to create one 2-hour video off of the source files, to eventually put onto a dvd-r to watch -- (as i realize the quality won't be as good, at a lower bit rate that is why i'm archiving each hour on seperate discs). I preferred using CBR to VBR because in the past VBR didn't look as good to me (on some videos, of course this is all subjective, in any case, i'm just trying to create a single Constant Bit Rate mpeg 2 file).

Okay so I loaded both clips into video editor, synced them up, and created a video. I set the output clip to CBR, at full size of 720x480, and the bit rate to different values. However no matter what value I seem to choose, the file ends up being exactly 3,800,000 (give or take a few k, but always the same no matter what bit rate i choose).

I hope I've covered everything, if not, i'll try again.

Why doesn't MSP want to encode my video using constant bit rate, at the rate I specify?

The resultant file always ends up being variable bit rate, even though I explicitly checked the CBR box.

Tonight I will raise the bit rate to 8k -- just to see if i can make the output file size any different.

Thank you.
Keith Weatherby II
http://www.gamesafoot.com
Uhfgood -AT- verizon -DOT- net
troppo
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Post by troppo »

Uhfgood wrote:Does h.264 encode into a dvd? How big are the file sizes compared to mpeg 2? Can I get a free implementation? I thought mostly quicktime used h.264?

As you can see I know nothing about it, which is probably why I'm not encoding in that.
H.264 has been developed to serve HD over the air. It's also the preferred format that Adserve requires when delivering TV ads. It doesn't encode to DVD, but then neither does a 10,000kbps MPEG file. The file sizes depend on the bitrate, however at any given bitrate it will be much better quality than a MPEG of the same bitrate.
Quicktime is a container, like AVI, not a codec in itself. A h.264 file can be an AVI or a MOV or even something else.
Dont know if it's free, it came with Final Cut Pro on my system.

And I'm sorry I cant help with your unusual MPEG encoding problem in MSP, but I have always found the MPEG encoder in MSP to have a mind of it's own when it comes to bitrates.
http://www.broomevideo.com
Uhfgood
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Post by Uhfgood »

You're right a 10kbps mpeg file doesn't really work for dvd. I'm using those as sort of my highest quality backups. Granted I could get better quality with some other codec, but at the size the files are work for my purpose.

I just don't have money to buy final cut pro and a mac to go with it. (on pc :-)
And I'm sorry I cant help with your unusual MPEG encoding problem in MSP, but I have always found the MPEG encoder in MSP to have a mind of it's own when it comes to bitrates.
I'm just finding that out. I recently uninstalled and reinstalled msp, and i was using the same dvp file, so it's possible that something is locked up within that file. I will attempt to recreate it, and re-render to see what happens.

I don't know why but before I got msp to create a regular cbr file at about 4000 -- but then again, maybe it was doing the same thing, and I didn't know it. That was when I was on win2k, but now i'm on win xp home.

Anybody else know why msp won't create a video file using constant bit rate at any rate i specify?
Keith Weatherby II
http://www.gamesafoot.com
Uhfgood -AT- verizon -DOT- net
Uhfgood
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Post by Uhfgood »

If anyone is still reading this. I recreated the dvp file, and re-rendered at 6144, and now it's at around 5.6 gig. Finally the size changed. Now tonight I'm going to test it by changing the bit rate to see if it was a problem in the dvp file I had saved. If it was then when I change the bit rate the size should be different yet again. If not, then I will have to recreate the dvp file yet again to change the bit rate.

GSpot still claims it's a VBR file, even if it did encode around the bitrate I selected.
Keith Weatherby II
http://www.gamesafoot.com
Uhfgood -AT- verizon -DOT- net
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