Bitrates: TMPGEnc Settings for use W/ CQmatic on PAL Movies

rds_correia · #1 09-08-2003, 03:17 PM

Hi guys,
I was just wondering about the KVCD specs that Kwag published recently and I'm a bit puzzled about some details:
1 - Kwag mentions "It's also recommended to set "Scene change detection", if the encoder permits." but I have seen on this forum Kwag saying that if u use CQMatic u will have to disable this feature from the encoder. Should it be disabled just for prediction and reenabled by the time u start encoding???
2 - Kwag says "Suggested bitrates are a minimum of 64Kbps and a maximum of 3,000Kbps. For MPEG-1 and MPEG-2 in this bitrate range, a DC component precision of 8 bits is recommended." but when I download the latest KVCDx3 MPEG-2 template it comes configured to 300-2500Kbps and with DC component of 10. Again should this be disregarded when encoding and just used for prediction with CQMatic???

I say this because more than once I've seen Kwag posting in this forum that the bitrate should be set to .57*AvgBit-2000. But I've also seen Kwag saying that if we shoot for a 2 CD encode then we should set the high bitrate to 2500......

3 - Now the most confusing: the KVCDx3 MPEG-2 template comes configured to High quality (slow) motion search precision. Again I've seen Kwag saying that we should use "motion estimate search (fast)". What to do???
Do some of these settings differ if one is using avisynth 2.08 or 2.52?
I'm using 2.08 because it seems very reliable and because I can use MStacker to build it easy. But if someone tells me to use 2.52 because it's faster (which I haven't been able to proove) than 2.08 when using MA because one can set "motion search precision" to "motion estimate search (fast)" and the quality will be the same as in 2.08 but faster then maybe I can start understanding why you guys are all very excited about 2.52.
I think that someone should start some kind of reference KVCD specs when using TMPG with CQM but that's only me thinking...

kwag · #2 09-08-2003, 03:25 PM

Quote:

Originally Posted by rds_correia

1 - Kwag mentions "It's also recommended to set "Scene change detection", if the encoder permits." but I have seen on this forum Kwag saying that if u use CQMatic u will have to disable this feature from the encoder. Should it be disabled just for prediction and reenabled by the time u start encoding???

No. Leave it on. I mentioned that on very early versions of CQMatic.

Quote:

2 - Kwag says "Suggested bitrates are a minimum of 64Kbps and a maximum of 3,000Kbps. For MPEG-1 and MPEG-2 in this bitrate range, a DC component precision of 8 bits is recommended." but when I download the latest KVCDx3 MPEG-2 template it comes configured to 300-2500Kbps and with DC component of 10. Again should this be disregarded when encoding and just used for prediction with CQMatic???

I haven't updated the templates in a while, because we're now geared towards encoding parameters, instead of templates. So the original KVCD "templates" are way gone

So use the suggested parameters with your favorite encoder.

Quote:

I say this because more than once I've seen Kwag posting in this forum that the bitrate should be set to .57*AvgBit-2000. But I've also seen Kwag saying that if we shoot for a 2 CD encode then we should set the high bitrate to 2500......

That's for more accurate prediction, and it's related to TMPEG.

Quote:

3 - Now the most confusing: the KVCDx3 MPEG-2 template comes configured to High quality (slow) motion search precision. Again I've seen Kwag saying that we should use "motion estimate search (fast)". What to do???

Use Motion Estimate (fast). Again, those templates are far from the current parameters.

Quote:

Do some of these settings differ if one is using avisynth 2.08 or 2.52?
I'm using 2.08 because it seems very reliable and because I can use MStacker to build it easy. But if someone tells me to use 2.52 because it's faster (which I haven't been able to proove) than 2.08 when using MA because one can set "motion search precision" to "motion estimate search (fast)" and the quality will be the same as in 2.08 but faster then maybe I can start understanding why you guys are all very excited about 2.52.
I think that someone should start some kind of reference KVCD specs when using TMPG with CQM but that's only me thinking...

Use AviSynth 2.52. It's faster than the 2.0x branch, and you'll get better quality, specially if you use the MA script. MA filtering is not possible with 2.0x.

-kwag

rds_correia · #3 09-08-2003, 04:46 PM

Hi Kwag!
You're the man!!!

BTW do u use DC component precision 8,9 or 10 with TMPGEnc 25xx?
Or what would you sugest?
One other thing: I'm trying to encode a 1h51m15s 16:9 DVD movie using CQMatic/CalcuMatic to predict. This is 111minutes and 15 seconds.
CQMatic doesn't let us insert seconds so I think I should choose 111 minutes, right? Also CalcuMatic says that my average bitrate is 1803.6 for a 2 CD encode and one audio track of 160Kbit.
I've been selecting 1803, but now I come to think that maybe I should use 1804 since it's >= 1803.5.
What do u do in these cases?
Thanks for ur fast reply

.

Dialhot · #4 09-08-2003, 05:20 PM

The precision of CQMatic is of few percents. Rounding the minutes length or the bitrate calculated will only add dust of percents more. Don't worry about this !