Artifacts on a finished DVD...is 4.6 GB too much for a DVD-r?

[Huntr777]

Hello all, been a while since I posted on here. I have been busy learning Final Cut pro and DVD Studio Pro. One problem I have is this, I am making up a DVD with FCP, and exporting it to DVD SP, the video looks fine when I edit it in FCP, then I export it using Compressor 4, with the settings for a 120 minute disc. It spits out a 4.6 GB file which I then put into DVD SP to menu and author it to disc. When I burned the disc I checked it out on my TV and saw some artifacts, one video clip was so bad it wasn't even watchable. Is 4.6 GB too much to expect good playback?

The average bitrate was set for 5 MBPS (which equalsi 90 minutes of video...interesting since the setting I'm using said it's for "best quality 120 minutes")...so I lowered it down to 4 MBPS (which equals 112 minutes of video, which is exactly how long the DVD I am making is) and then did a new compression on it...to find that once again the artifacts are still there.

So I throw this open to the Mac community at large, what should I do? Do I crank down the bitrate to around 3.6 MBPS which would equal a full 120 minute DVD? I would like to keep the quality at 5 MBPS but obviously can't have the artifacting.

FYI I am doing some footage from VHS tapes so I am not expecting HD quality here, but I do want the quality as good as it can get. Any help , anybody?

Tom

[tomlee59]

Take a look at commercial DVDs that are 2hours or so on a DVD5: Not much "unwatchable" artifacting there, right? So that's one answer to your question.

The old adage of "garbage-in, garbage out" remains true. If your source isn't clean, the result won't be. Also, if your workflow involves multiple transcodes, you're going to suffer quality loss in the process.

The general keys to success are:

1) Start with high quality source material. VHS and DVD are not those, but if that's all you got, then that's going to set a possibly unacceptable floor on quality.

2) Perform as few transcodes as possible. If you need to edit, then transcode to, say, DV, and do all of your edits on that one version.

3) Do only one more transcode to your final ("delivery") format. Use the highest bitrate practical.

If the source is very noisy (e.g., it was recorded off the air, or is from a poorly treated tape), then some prefiltering will help a lot. White noise ("snow") eats lots of bits to encode, so filtering reduces the waste of bits, crudely speaking, at the expense of some softening of edges.

And if your source has dropouts, that can cause very bad artifacting indeed. MPEG is not robust with regard to dropouts -- the effects will propagate over at least one GOP. If you have a particularly error-filled source (e.g., abused videotape), sometimes reducing the GOP (if allowed) will improve perceived quality by limiting the extent (temporally) of a dropout's effect.

[edDV]

What was your source file?

It wasn't 4.6GB, it was "120 minute disc" and "5 MBPS" and "4 MBPS".

Instead try "60 minute disc" and more than 8 Mb/s for video stream.

If you have problems after that, please explain the source in more detail.

[edDV]

Take a look at commercial DVDs that are 2hours or so on a DVD5.

Most commercial DVD discs are pressed and two layer with close to an hour per layer.

I agree with the rest of what you say.

[jagabo]

I am doing some footage from VHS tapes

This is your problem. VHS tape is very noisy. Unless you have a time base corrector it also has timing errors what cause edges to move horizontally from frame to frame. Those defects consume a lot of bitrate.

If you really need to put more than an hour of VHS on a single layer DVD use 352x480 resolution instead of 720x480.

[tomlee59]

edDV: I understand that most 2-hour discs today are that way. But my statement was different, and carefully worded: There are 2-hour commercially pressed DVD5s. And these do not suffer the horrible problems alluded to by the OP.

[guns1inger]

If your audio is 2 channel and compressed at a reasonable 224 kbps, then the average video bitrate for 112 minutes is a little over 5200 kbps. Make this a 2-pass VBR encoding with a maximum of around 8700, minimum of 1000 and 5200 as the average, and the quality, while not steller, should be acceptable.

if you don't have an encoder that gives this level of granularity in the settings then you are in for quality issues. For example, 4 MBp/s allows for 2 hours 24 minutes of video on a SL DVD with 224 kbps audio.

[edDV]

I missed or forgot he was capturing VHS. I usually withdraw from VHS discussions.

As far as I know you get what you get.

I have a pallet load of great VHS tapes in a cool dry basement that I'm preserving for restoration. Once the secret formula is revealed, I'll get busy.

[guns1inger]

If you want even reasonable quality for VHS transfers you need hardware, and lots of it - TBS, filters etc. Or you need to learn avisynth (hardware is better, as cleaning up after the fact is always inferior). VHS needs a lot of clean up to get acceptable results, and if you are serious about quality, either author for dual layer, or keep the running time down to less than 90 minutes. If you must push 2 hours, consider encoding at half-D1 resolution.

Tools such as Premiere, FCP etc are not designed to handle or clean up VHS captures. They expect nice, clean, digital source. If you are working with VHS you have to accept that it takes a lot of work, you have to get your hands dirty, and you have to meet it half way.

[jagabo]

The easiest and cheapest, reasonable quality, solution for VHS->DVD is to get a DVD recorder with built in TBC.

[Huntr777]

Hmmm checked all of the settings and everything seems to be OK...I do have to point out that when I did the exact same thing in iMovie to iDVD years ago (with the same footage mind you) my end product came out with no problems. Seeing how DVD Studio Pro gives you more control over what comes out I just have to tweak some things to not have the problems happen...anybody else have the same problems?

T

[guns1inger]

The numbers you were quoting in your first post for fitting footage onto DVD are simply wrong. Use a bitrate calculator to check what numbers you should be using. Low bitrates increase the incidents or artifacts. 5 MBp/s is barely acceptable as an average for good quality source. For VHS it is simply asking for problems.

[terryj]

gunny is right Hunter.
using this tried and true Bit Rate Calculator
your target bitrate should have been 5.35 to 5.61MBPS.
(with audio bitrate set at 192kbps)
If You had edited it down to say 1h30m , with 192kbps audio
you should hit a target Bitrate of 6.5 MBPS, which is more acceptable quality.

If you can't cut your edit down to hit 90mins ( even say 95 minutes at max),
you can cut the audio down to 160 kbps, and hit a target of 5.6 to 5.9MBPS.
But I wouldn't go less than 160kbps on the audio, I'd just trim to make
the 90 to 95 minute run time.

The higher your target bitrate, the better your encode.
If you hit the 95 min max on your edit, set Compressor to target the encode
between 5.6 ( low) and 8.0 (max), at VBR ( Variable BitRate).
You should get an average around 5.9 to 6.2 and acceptable quality
( for VHS).

[redwudz]

Sorry, coming in a bit late in this discussion, but the thread title interested me. A DVD-5 disc can hold about 4.37GB, so 4.6GB would be a problem.

The VHS cassettes I've converted to digital generally needed a TBC and a fair amount of filtering, hardware preferred, to get a reasonable video facimile of the original cassette. I also use 1/2 D1 a lot as most of my tapes were recorded in LP. That gives me a lot more bitrate bandwidth to play with, and with my VHS sources, full D1 is overkill anyway.