Can someone explain these numbers?

[frink]

I encoded a movie that was 2:20 long in 2pass VBR with 400kbps min.(padding enabled), 1400kbps avg., and 2200kbps max. with 128kbps audio. The resulting file was roughly 1.3gig. I used Vdub to exract audio and used that WAV with the original AVI to create it.(motion search precision=high quality)

I then encoded a movie 2:16 long in 2pass VBR with 300 min.(padding enabled), 1500kbps avg., and 2200kbps max., with 128kbps audio only this time the resulting file was only 935mb. The only difference was that instead of extracting the audio and creating a WAV. I had to save out a copy of the AVI without bad frames, and then I used it as botht the video and audio source in TMPGEnc.(motion search precision=highest quality)

Now, what caused the discrepancy in file sizes? Was it the fact that I used the AVI for encoding in the second movie instead of a WAV, and if so, why would I ever use a WAV again, or did the motion search precision setting have something to do with it? I welcome any help or advice!!!

[matneaves]

i think its th VBR, which is variable bitrate, so size will change, i always use CBR (constant bitrate) option, and when i change the bitrate, the final size is what i expected

http://www.data-uca.150m.com/vcdencoding.doc

have a look, might help

[RabidDog]

try encodeing video and audio seperarely. No way should the final size of movie be any bigger than the size of the two files added together? . straight wav file on a movie can be around 1Gb mark??

[donpedro]

Are they two different movies or same movie ? If different, your size will depend on what is in movie. What kind of scenes.

[frink]

They were different movies, so I will provide a new example of the problem I am having.
This is two different encodings of the same movie.

Movie length: 1:40:33

Example 1

2pass VBR
Avg. 2000 kbps
Max. 2400 kbps
Min. 600 kbps
Padding On
Audio 128 kbps

File size= 1.01 Gb

Example 2

2pass VBR
Avg. 2600 kbps
Max. 4000 kbps
Min. 600 kbps
Padding On
Audio 192 kbps

File size= 1.02 Gb

Shouldn't the file size of example 2 been a lot larger? Its the same movie but with a way higher bit rate. There must be a problem. Any help would be great.

[frink]

This thread went dead about a month ago, so I guess its OK to move it up a little bit. I continue to have this problem with the movies I encode. I stopped worrying about it and just burned the movie on to 2 disks (wasting a ton of space) but now the problem is really starting to piss me off. I've tried re-installing TMPGEnc, and VDUB and it made no difference. My last attempt was an XVCD encode of "The fast and the furious" my settings in TMPGEnc were:

Movie length: 1:46:37

2pass VBR
Avg. 3200kbps
Max. 3800kbps
Min. 600 kbps
Padding on
Highest quality
Audio 224kbps

The resulting file size was a mere 1.19gb
I'd say something is obviously wrong with that. I would think the file size with those numbers would be somewhere around 2gig.
So, if anyone has any idea whatsoever please let me know. If I have to wait another month for a response my next conversion will be converting my computer to a door stop.

[Gazorgan]

Some movies are smaller than you estimate. Movies with little action are like this. The only thing guaranteed is the minimum bitrate. In theory you could never hit your maximum bitrate (although this would be rare, or the bitrate is too high). You Average Bitrate 'should' determine you final size (Avg Video Rate+Audio Rate) *( Length ).

Now as to your problem. I have to translate in my head, since I do xSVCD. Remember, no matter how high you set the bitrate, there is some point where it won't use it. Some scenes are 'maxed out' at 1500 or 2000 and won't go any higher.

Now, big question, are you actually making an xVCD? You file size is indictitive of a VCD. You have to use a non-standard template in TMPG, otherwise it will stick with the VCD setting of 1150. Sometimes making a xSVCD it does that and set's the max to 2250 instead of 3500. The file size you give is higher than a VCD should have, by maybe 15%-25%.

Try a CQ encode instead of 2-pass VBR.

[frink]

I am Definitely using a non-standard template. I checked the proper box, and when the encoding is being done the information being displayed is the numbers that I put in there, not the standard VCD numbers(1150kbps). What is the quality difference between CQ and 2pass VBR? I just read that if the settings are right then CQ is better than VBR. If this is true, do you have any suggestions of good settings for CQ?

[frink]

Also, The numbers are very high in the example I posted. What I failed to mention is that I have encoded that movie several times using various VBR settings and the resulting file size does not change all that much.

[DKruskie]

I use headac3he to make the ac3 wav a mp2 file at 128kbs saves alot of space.
For instance the movie I'm doing now, the Ac3 wav file was 946mb while the Mp2 files was only 80.3 mb. Makes alot of difference for me, to me the audio sounds better and I have less insync problems.


David

[frink]

I'm still looking for good settings for CQ in TMPGEnc. Also, what does P and B picture spoilage mean, and do I have to change those numbers when using CQ?

[jarroyo]

Frink,

One thing I would suggest is that you download bitrateviewer from the tools section and evaluate the bitrate throughout your movie with it. You will get a better feel of how the bitrate is changing at the different points in your movie since it gives you a continuous graph.

You can then compare example 1 vs 2 more accurately.

[bugster]

Are you encoding mpeg-1 or mpeg-2. I ask because, if it is mpeg-1, you have to set Stream type (on the settings, system tab) to either mpeg-1 video-cd (non standard) or mpeg-1 system (VBR) for your bitrate changes to have any effect. Also there is one version of Tmpgenc around that has a bug and still encodes at VCD bitrate irrespective of settings.

[frink]

I use mpeg-1 video-cd(non-standard). I wondered if I should use the mpeg-1 system (VBR) option, but ZippyP told me I needed to continue using the non-standard template. Would you agree with this? And if so, then what is the mpeg-1 system (VBR) option for?

[frink]

Could using the non-standard template for a VBR encode be causing my file size troubles mentioned above?

[Donny661]

Stick with Video-cd (non-standard) if your going to burn to vcd. mpeg-1 system (vbr) would be better if your going to keep it on your computer. There's something to do with packet sizes, buffers, mux rates, ect. that are the differences between the two.

CQ mode just gives you settings for the max and min bitrate and a quality setting. the encoder will make one pass through the video and vary the bitrate so that each frame is the same quality. There are long threads as to wich one is better so lets not discuss that. The downside to CQ is that filesize is completely unpredictable so you might have lots of wasted space on a cd, but 2-pass takes forever.

As to your filesize problem. Make sure you put the values in the right box because one time I mixed the max and ave. and my filesize was messed up. The only other thing that I could think of is there might be a bug in that version of TMPG so try upgrading (or downgrading )

[bugster]

What version of TmpGenc are you using. Apparently 2.59.47.155 had a bug that screwed this up. See this thread here:

https://www.videohelp.com/forum/viewtopic.php?t=149948&highlight=

[frink]

I'm using the newest version of TMPGEnc (2.51) I think I'll reload it for the 3rd time and see if that makes any difference.