Transcoding DV Avi to Mpeg2 - bitrate calculator help

[BustaCap]

I've been soaking up as much as I can reading the tuts and articles here but I must be missing something because I ran into an unforeseen problem. I am trying to capture a VHS tape, convert to mpeg2 and then burn to DVD. This is my setup and workflow so far:

Win XP, 120GB x2 WD, Canopus ADVC-100, low-end VCR. The tapes I am capturing are 60 minutes in length x3 and I want to fit all 180 minutes on one DVD. These are instructional tapes and I am not too concerned about the quality although I don't want them to look terrible.

1. I capture DV Avi with Premiere Pro, edit as necessary.
2. Using the bitrate calculator with the following variables:

• 3 hour length
• Type is DVD
• Bps, 1kbit=1024 bits
• Audio bitrate=128 kbit/s x 1 tracks
• Iso 25 MB/DVD

And the calculator gives me 3181 kbit/s and DVD Max Bitrate of 9442 kbit/s

3. I transcode using Adobe Media Encoder with the following settings:
Video Summary:
Codec: MainConcept MPEG Video
Video Type: MPEG-2 Video
Quality: 5.00 (high quality)
TV Standard: NTSC
Aspect Ratio: 4:3
Frame Rate: 29.97 fps non-drop frame
Program Sequence: Interlaced
Field Order: Lower
Bitrate Encoding: VBR
Target Bitrate (Mbps): 3.1810 (low quality)
Maximum Bitrate (Mbps): 9.3000 (medium quality)
Minimum Bitrate (Mbps): 1.2000 (low quality)
Encoding Passes: Two
M Frames: 3
N Frames: 15
Closed GOP every: 0
Macroblock Quantization: 10
VBV Buffer Size (2K bytes): 112
Noise Control: Noise Sensitivity
Noise Sensitivity/Reduction: 5

Audio Summary:
Codec: MainConcept MPEG Audio
Audio Format: MPEG-1 Layer II Audio
Audio Mode: Single Channel (Mono) Mode
Psych Mode: Psychoacoustic model 2
Bitrate (kbps): 128
Sample Rate: 32 kHz
De-emphasis: No emphasis
Enable CRC: Off
Set private bit: Off
Set copyright bit: Off
Set original bit: Off

Multiplexer Summary:
Multiplexing Type: MPEG-2
Bitrate Type: Constant
Packet Size (bytes): 2048
Packets per Pack: 1
Sectors Delay (ms): 0
Video Delay (ms): 180
Audio Delay (ms): 180
Video Buffer Size (kB): 0
Audio Buffer Size (kB): 4
Mux Rate (kbps): 0
Max file size (MB): 0
Pulldown: Auto
Frame Time stamp: All frames
Write Program end code: On
Align Sequence Header: Off


I tested this on a 12 minute DV Avi and was expecting to get a Mpeg file of approximately 300 MB (12 minutes is about 7% of 180 minutes, so 7% of 4479 MB is 300 MB). However, the Mpeg was 872 MB

Obviously, I'm doing something wrong here. Any ideas on what I should change in my encoding setup? Did I use the bitrate calculator incorrectly?

---
BC

[FulciLives]

Using a BITRATE CALCULATOR and a 3 hour running length I get a VIDEO bitrate of 3126 using 256kbps audio (be it MP2 or AC-3 either way same size). I wouldn't suggest going lower than 256kbps for the audio. Maybe 224kbps but that only raises the VIDEO bitrate to 3159kbps which ain't a big difference.

I don't use MainConcepts so I can't offer much help there as far as the settings go but I did notice you are using 128kbps MP2 audio and that is MUCH too low. You really should use 224kbps if not 256kbps

Other than that my only other suggestion is to use half D1 resolution for the final MPEG-2 file. That is 352x480 NTSC

That size will look MUCH better than full D1 (720x480) at the low bitrates you are using.

Also one other note. I wouldn't set the MAX video bitrate to higher than 8000kbps and the low can go as low as 1000kbps but I wouldn't go lower than that.

Also I tend to be conservative with my bitrate settings so even though I got 3126 I would probably use 3100 instead. Never a good thing to cut it too close to the final size. And yes I was using an ISO overhead of 25MB in the calculator (I used the one on this site).

- John "FulciLives" Coleman

[BustaCap]

John, thanks for the quick reply. If I encode at 352x480 NTSC, will I still be able to burn to DVD? Don't I have to use 720x480 to burn to DVD?

[FulciLives]

John, thanks for the quick reply. If I encode at 352x480 NTSC, will I still be able to burn to DVD? Don't I have to use 720x480 to burn to DVD?

352x480 (also called Half D1) is a valid resolution for DVD. Only a Full D1 (720x480) transfer can be anamorphic so you can't make Half D1 352x480 anamorphic but otherwise there are no restrictions on using it.

Since the source is VHS you will not notice any loss in quality by going to Half D1 (352x480) and the nice thing is that the lower resolution of Half D1 needs less bitrate to look good.

It is a win win situation especially when the source can't really support the higher Full D1 resolution ... which is the case with VHS captures.

As for the audio ... well even shitty looking VCD uses 224kbps MP2 audio so going lower than that is just not a good idea. You could get away with 192kbps if using AC-3 but 224kbps for MP2 is sorta like considered the lowest you would want to ever go and still get acceptable quality audio.

- John "FulciLives" Coleman

[sitlet]

dont know if im too late here, but instead of using vbr, use cbr at about 3000. if you want to use vbr, set about 3000 for the target, maybe 4000 max and 2000 min. by setting the max at 9300, that means the bitrate ould go up that high, making the file larger

[FulciLives]

dont know if im too late here, but instead of using vbr, use cbr at about 3000. if you want to use vbr, set about 3000 for the target, maybe 4000 max and 2000 min. by setting the max at 9300, that means the bitrate ould go up that high, making the file larger

Sorry but this makes no sense at all.

There is no problem in doing this as a 2-pass VBR encode. The only problem is that 8000kbps should be the MAX bitrate used for the MAX setting otherwise you run the risk of going out of the DVD spec and making a DVD that is hard to read.

But anyway you cut it slice it dice it the final file size when doing a 2-pass VBR is dependant on the AVG bitrate and not the MAX or the MIN values.

- John "FulciLives" Coleman

P.S.
If I was doing this myself I would probably set the MIN to 1000kbps the AVG to 3100kbps and the MAX to 5200kbps and of course use Half D1 (352x480) resolution. I like setting the AVG directly in the middle of the MIN and the MAX but I don't like going less than 1000kbps for the MIN so that is how I got the values I got. Afterall 5000kbps is about the MAX bitrate that Half D1 can really use anyways.

But you could set your MAX to as high as 8000kbps if you want.

[BustaCap]

It looks like the problem I am having is somehow related to Premiere. Using your recommended settings I'm still getting a file size about 2.5x the expected size. Also, I can't seem to encode to Half D1.

However, using TMPGEnc to encode everything comes out exactly as expected and I can encode to Half D1, so I guess I'll just edit in Premiere and encode with TMPGenc. Thanks for the help

I normally use Adobe Encore to author my DVD's, but Adobe doesn't play nice with Half D1 files. I tried out the TMPEGEnc DVD program but there doens't seem to be much flexibility when creating menus. Can you recommend another authoring program that can handle Half D1 files?
----
BC

[FulciLives]

It looks like the problem I am having is somehow related to Premiere. Using your recommended settings I'm still getting a file size about 2.5x the expected size. Also, I can't seem to encode to Half D1.

However, using TMPGEnc to encode everything comes out exactly as expected and I can encode to Half D1, so I guess I'll just edit in Premiere and encode with TMPGenc. Thanks for the help

Please note that you should be able to frame serve from Premiere to TMPGEnc but I don't use Premiere so I don't know how to do it exactly.

I normally use Adobe Encore to author my DVD's, but Adobe doesn't play nice with Half D1 files. I tried out the TMPEGEnc DVD program but there doens't seem to be much flexibility when creating menus. Can you recommend another authoring program that can handle Half D1 files?

Well you won't like my answer here I guess because I use TMPGEnc DVD Author ... mostly due to ease-of-use and the fact that it is a very stable program.

You might want to try DVD-Lab as a lot of people seem to like it but I've found it to be a bit too "buggy" for my use. There is a trail period of something like 2 weeks or 4 weeks before it locks up and needs to be bought/registered.

Anyways the Adobe Encore thing is an anomaly in that most DVD authoring programs have no trouble with Half D1 but you know Adobe ... they have to do things "their" way.

It might be worth poking around a bit ... I think I read that there is a "trick" that can force Adobe Encore to accept Half D1 files.

- John "FulciLives" Coleman

[racer-x]

A couple of things, You have 32khz audio.........it must be 48khz for DVD.

You can use the PluginPack frameserver in the tools section to frameserve the timeline to TEMPGEnc or any encoder for that matter.

The average bitrate setting in the encoder is just an estimate, it is rarely acurate.

DVD-Lab works great and I recomend it highly.

[BustaCap]

Thanks guys