Which is the better option? (Splitting to two DVDs)

[TheGame7]

I have a sports event which is 4 hours 30 minutes in length (you may have read a post about this before, when I was wondering what settings to encode at).

Unfortunately, when encoding this footage to fit on DVD-R, the loss is quality was far too poor for my liking (as its for collection purposes rather than one time viewing). Consequently, I have decided to split the event onto 2 DVDs.

My question is, once I have the avi, whats the better option?

Cut the avi into two first and then encode to mpeg-2?

Or, encode first at 8000 CBR (or 5000 if I use half d1) and then split it accordingly?

Any help much appreciated.

Thanks.

[daamon]

Hi TheGame7,

What's the source of the footage? i.e. VHS, camcorder etc.?

If it's VHS, I'd say trim it down to as short as possible (i.e. remove ads, anything you can live without), and go with 1/2 D1 @ a bitrate of around 2,500kbps, if you can get that high (4.5 hours = 2,000kbps, quality might be OK, just - and you'll get it on one DVD), given the upper filesize limit of 4.37Gb - use the DVDRHelp Bitrate Calculator to judge.

This presumes you're gonna use compressed audio and not disc-hungry WAV (PCM)...

If it's higher quality (i.e. DV cam) then 2 discs is the only real option if you want quality. Again, use the bitrate calculator for the bitrate to use. Split the AVI before encoding to MPEG2 as this is far less likely to cause problems (i.e. audio sync is common when splitting MPEGs). Use VirtualDub to split the AVI.

Either way, as disc space is a premium, compress your audio to AC3 (OK in NTSC & PAL lands) or MP2 (OK for PAL land, probably OK in NTSC land though not part of the NTSC DVD spec). Extract the audio from that AVI as a WAV (VirtualDub can do this - make sure it's at 48,000Hz), then use ffmpeggui to compress to your chosen format.

Also, again as disc space is tight, encode (I'm presuming you're using TMPGEnc here) using 2 pass VBR, min = 1,000, average = XXX, max = YYY, where:

XXX = Bitrate from the calculator
YYY = 8,000kbps for high quality source (DV cam) or 5,000kbps for a source like VHS.

This link might be of use if source is VHS:
https://www.videohelp.com/forum/viewtopic.php?t=206798&highlight=

Hope that helps. Good luck...

[TheGame7]

Thanks for the detaled reply.

The source is sattelite TV and 2500 bit rate is not enough.

I will follow your advice about splitting the file.

Is VBR stll required if I am splitting to two 2 hr 30 mins dvds?

[daamon]

Thanks for the detaled reply.

No problem - I find it's easier to give detail up front - saves a load of questions back and forth...

Is VBR stll required if I am splitting to two 2 hr 30 mins dvds?

It's not a "must", but 2 pass VBR can result in smaller filesize. I'll explain:

CBR: Constant Bitrate - Encodes are done at the same bitrate throughout, irrespective of whether a high bitrate is needed for a scene (e.g. fast motion, lots happening) or a low birate is needed (e.g. static background, not much movement). This will result in a file of easily determinable size (file size is only a function of bitrate and running time in seconds).

2 Pass VBR: Variable Bitrate - A quote from this guide:

Quote: "In 2-pass VBR mode, the compressor will make two passes. In the first pass, it will compress the footage while trying to keep a constant quality, regardless of bitrate. It will then use the resulting bitrate (scaled to fit within the user-selected values) to do the final encoding. This results in the best relationship between compression and quality. It is, however, rather slow.

If you use CBR at 8 Mb/s, you will end up with more or less the same quality, but the compression will not be as efficient. This means that the resulting file will be bigger, and you will not be able to fit as much video into one disc. If your movie has less than 1 hour, and you don't have any use for the extra space on the disc, you should use CBR to save on the encoding time." Unquote. This last sentence is the opposite of what you're wanting to achieve, hence why I recommended VBR.

If using VBR, remember to set the average as that calculated using a bitrate calculator. Don't be tempted to go for a higher minimum (common mistake) as this just means that scenes only needing a low bitrate will forced to be encoded at a higher one and so "stealing" valuable bitrate from scenes that need it.

The bitrate setting may seem low, but, because of the nature of VBR, you'll hopefully still get the quality (so 2,500kbps may be enough). Try it out on short clips to judge for yourself. You may need to do it over 3 discs.

If you're gonna use compressed audio (recommended), then a max of around 9,000 kbps should be used for the video during encoding.

The source is sattelite TV...

Mmm... Not sure what resolution that's delivered in. If it's low resolution (normal TV - 352 x 240), then you can do 1/2 D1. If it's higher, you may need to go higher. 1/2 D1 may still be OK though... Experiment on short clips.

That should answer your question...

[TheGame7]

Thanks for another brilliant reply.

I think that clears up everything.

If I hit any stumbling blocks, I hope you don't mind me asking for assistance again.

[daamon]

Thanks for another brilliant reply.

Easy, I'll either get bold or bashful . Glad you appreciated it though.

I think that clears up everything. If I hit any stumbling blocks, I hope you don't mind me asking for assistance again.

Good. Of course not. I learnt from the generosity of others, only fair to pass it on...

[TheGame7]

I am using Canopus' ADVC-55...

What codec do I need to open its avi's in Virtual Dub?

How do I go about installing the codec?

Cheers.

[daamon]

Hi TheGame7,

What codec do I need to open its avi's in Virtual Dub?

I'm not familiar with any of the Canopus tools, so I can't say for sure what type of AVI it captures into. But, that's not a problem - just use either GSpot or AVICodec and they'll tell you what type of AVI you have, what codec you need and whether it's installed or not.

How do I go about installing the codec?

It's highly likely that you'll find what you need in the "Codecs" section on this site (under "Tools"). Download the relevant file and follow the install instructions.

If you need a DV codec (identified by 'dvsd'), apparently the Panasonic DV Codec works excellently with VirtualDub.

Hope that helps. Post back if you need more...

[TheGame7]

Just remembered where I got the idea of splitting avis...and it was from here.

@daamon

You suggested splitting the avi and then encoding...

Well I wondered, would this mean that there will be two new avis added to the hard drive or is it split in real time?

I am worried about this since I have a 100GB file that will be split and the hard drive is 160GB in size..

Also, can I clip the start and end of the avi too?

[daamon]

Hi TheGame7,

...would this mean that there will be two new avis added to the hard drive or is it split in real time?

Yes, two new AVIs. Therefore, no.

Since your tight for hard drive space (only 160Gb!), you could set the start and end points in VirtualDub and then frameserve to TMPGEnc to encode. "frameserving" gets round having to have an intermediary file (as you would if splitting) by serving each frame (hence "frameserving") of the AVI (via memory) to TMPGEnc when it's ready to encode it.

I've not frameserved from VirtualDub to TMPGEnc, but I know it's possible and would be surprised if there wasn't at least one decent guide.

Also, can I clip the start and end of the avi too?

With VirtualDub, yes. I can't recall exactly how to do it, but it is fairly intuitive. I would normally look into it and advise, but it's 2a.m. and I'm starting to wane...

A word of warning - when you're saving AVIs in VirtualDub, it saves them as uncompressed unless you direct it to otherwise. That's where the Panasonic DV Codec comes in that I mentioned above. You get VirtualDub to pick up your settings for audio and video (done separately) by selecting "Full Processing Mode" for either.

Hope that helps. Good luck, and good night...