Encoding for best quality and speed

[Jiao]

I was just wondering what is the preferred setting to achieve the best quality at a good amount of time encoding to mpeg2? Are VBR modes only to optimize the quality/space ratio? For instance, if I encode at 8000kbps at constant bitrate, will it produce the same quality as VBR but only bigger? Also, does doing a second pass at constant bitrate improve the quality? Finally, how does constant quantization with a quant value of 1 compare with constant bitrate technically?

Oh yea, and what's the difference between directshowsource and avisource? I seem to be getting some audio desync when using avisource.

[edDV]

Multi pass VBR is mostly about distributing bitrate where needed. If you max the bitrate at >9000 CBR then the quality is maxed. VBR gets more recording time by lowering bit rate in lower motion scenes. Multi-pass is about optimizing VBR.

[Jiao]

yea, so is it useless for constant bitrate?

[manono]

I was just wondering what is the preferred setting to achieve the best quality at a good amount of time encoding to mpeg2?

Run a Constant Quality encode with a decently high max bitrate. It'll run only one pass, so you'll be using the least amount of time. The quality will be whatever you set. And you'll lose control of the final file size, but that wasn't one of your qualifiers.

CBR encoding might produce the same quality as CQ encoding, if the bitrate of one is the same as the max bitrate of the other, but the CQ encode should be a good deal smaller in size.

AVISource should be used in preference to DirectShowSource whenever possible. Any audio asynch you're getting isn't because you used AVISource, but for some other reason.

[edDV]

In the encoders I've used, yes.

You could encode at higher bitrates but is won't be a compliant DVD.

[Jiao]

CBR encoding might produce the same quality as CQ encoding, if the bitrate of one is the same as the max bitrate of the other, but the CQ encode should be a good deal smaller in size.

Yes, size is not an issue. So, is CQ a little bit better quality than CBR at the same bitrate? I notice it takes a bit longer, but is it worth the wait? Doesn't a quant value of 1 mean it doesn't throw away anything?

[edDV]

CQ is another strategy to extend time vs. CBR but does not increase quality. For a given encoder all you can do is max the bitrate for 1x video. There are other issues such as handling stills, telecine and deinterlace.

[manono]

So, is CQ a little bit better quality than CBR at the same bitrate?

You ask that question after you quote me with my answer to that question?

but is it worth the wait?

You couldn't pay me to use CBR encoding. I reencode DVDs for DVD5, and CBR encoding is horrible for that.

Doesn't a quant value of 1 mean it doesn't throw away anything?

No, it doesn't mean that at all. Encoding for MPEG-2 is lossy, so even at the highest and best settings, you're still losing quality.

[turk690]

An MPEG-2 CBR of around 8mb/s creates video that's hard to distinguish from the original and I would use it if the particular DVD I was authoring has a program time of 1hour or less. Make that 2hrs if you are going to use something as luxurious as a double-layer DVD+R. Anything above 1hr program length (on a single layer DVD) will require VBR.

[guns1inger]

FWIW, rarely do speed and quality come together in the same sentence once you understand what you are doing. If you want it done fast, then forget about the quality. If you want quality, accept that the process will be more complex and the time taken will be longer, and revel in how good your output is.

[Abond]

Yes, size is not an issue.

Why mpeg2 then?

[Jiao]

To put it on a DVD, doesn't it need to be mpeg2 or can DVD's also play other formats?

FWIW, rarely do speed and quality come together in the same sentence once you understand what you are doing. If you want it done fast, then forget about the quality. If you want quality, accept that the process will be more complex and the time taken will be longer, and revel in how good your output is.

Well, shouldn't the process where the least optimizing is done be the fastest and produce the best results only with a bigger file?

Anyways, as turk690 suggested, I now do 8000kbps CBR 1-pass encodes with QuEnc. It takes about an hour for my 40minute episodes and the quality is very good. I don't know if it an get any better than this.

[45tripp]

I'd say it depends on your source, the quality you can 'live' with and the amount of time you are willing to spend.

AVISource should be used in preference to DirectShowSource whenever possible. Any audio asynch you're getting isn't because you used AVISource, but for some other reason.

Could it be due to VFW decoders not set up correctly or functioning as they should?

To put it on a DVD, doesn't it need to be mpeg2 or can DVD's also play other formats?

A lot of dvd players are mpeg4 compatible.
In that case you could encode to Divx or Xvid and put them in an Avi container with Mp3 or AC3 sound.
Nothing like mpeg2 quality though.
If you're starting with avi's though saves you some trouble.

Well, shouldn't the process where the least optimizing is done be the fastest and produce the best results only with a bigger file?

Yes.
But size is a big factor for many.
And encoding in CBR is essentially a waste of space.

Anyways, as turk690 suggested, I now do 8000kbps CBR 1-pass encodes with QuEnc. It takes about an hour for my 40minute episodes and the quality is very good. I don't know if it an get any better than this.

I believe the max total bitrate to be dvd compliant is just over 10000kbps (including audio bitrate). I'm sure some dvd players might not like very high bitrates but 9000kbps should be ok. Why not go up to 9000kbps if you only intend to put a single 40min clip on a whole dvd5?

Alternatively you could encode at 7000kbps and see how much difference there is to you. Because at 7000kbps you could safely put 2x40min (assuming they are actually 40min long and not say 45) clips on a sinlgle DVD5.

[Abond]

To put it on a DVD, doesn't it need to be mpeg2 or can DVD's also play other formats?

Well, then the size is an issue. Otherwise you can go with uncompressed.