MSP7.3 - Ulead MPEG Now encoder

gigi10 · Post by **gigi10** » Wed Sep 07, 2005 8:21 am

Hello,

My videos are always short, above 1 hour, and I'm looking for the best quality for final DVD.

[b]I've made several tests with a video 10'45'' length, from DV to MPEG-2[/b]

1 - VBR 8264 kbps => MPEG file 721506 ko bit rate average 7443
2 - VBR 2 pass 8264 > MPEG file 715596 ko bit rate average 7370
3 - CBR 8264 kbps => MPEG file 606270 ko bit rate average [b]6000[/b]
(these 3 tests done from the timeline)
4 - timeline --> encoding DV file 2407788 ko --> and then to MPEG-2
CBR 8264 kbps => MPEG file 606236 ko bit rate average [b]6000[/b]

[b]USV8 (full version) is also in my computer, so I've made 2 another tests with a small video (only video+sound sequence) :[/b]
USV8 : CBR 8264 kbps => MPEG file bit rate average 8251
MSP7 : CBR 8264 kbps => MPEG file bit rate average [b]6000 [/b]

[b]2 questions :[/b]

- Is something wrong in the codec, or in my computer ?
- in MSP8, will be the same codec or another ?

Best regards

Gorf · Post by **Gorf** » Wed Sep 07, 2005 9:15 am

???

You're not working out your average bitrate correctly.

1 - (721506 x

/ 645 = 8950
2 - (715596 x

/ 645 = 8875
3 - (606270 x

/ 645 = 7519
4 - Same as 3 (near enough)

I've no idea why CBR is not getting near it's intended bitrate. There's no reason for 2-pass VBR or CBR to miss the target. 1-pass VBR can be "forgiven" for not being close.

These bitrates are very high for DV material, and are probably too high for most DVD players to cope with, if put onto DVDR.

Devil · Post by **Devil** » Wed Sep 07, 2005 10:28 am

There are always unexpected surprises, but the differences are usually small. What you have not accounted for is the audio: which encoding method/bitrate did you use?

I'll expand on what Gorf said:

There is rarely anything to be visually gained from a DV source in going above 6000 kbit/s CBR (on longer projects, 6000 VBR max): you are not going to improve on the artefacts already present because of the DV compression. As he said, many players will not handle high bitrates with equanimity. Similarly, if you are encoding audio into AC-3 2/0, there is nothing to be gained above 192 kbit/s.

gigi10 · Post by **gigi10** » Wed Sep 07, 2005 12:18 pm

More precisions about my questions :

- parameters for MPEG encoding : PAL-DVD (720*576), 25 i/s, ratio 16:9,
non-square pixel, smart rendering,
audio : 49 Khz 1536 Kbps LPCM

- Bit rate average : calculated by VirtalDub, I think it is well calculated.

- for the tested file (10:46), the audio part weigths 121170 k.

gigi10 · Post by **gigi10** » Wed Sep 07, 2005 3:58 pm

I'm soory for the mistake :
audio : 44 Khz 1536 Kbps LPCM

gigi10 · Post by **gigi10** » Wed Sep 07, 2005 3:59 pm

I'm soory for the mistake :
audio : 44 Khz 1536 Kbps LPCM

Terry Stetler · Post by **Terry Stetler** » Wed Sep 07, 2005 5:05 pm

DVD requires an audio sampling rate of 48 khz, not 44.1 khz.

gigi10 · Post by **gigi10** » Wed Sep 07, 2005 5:35 pm

Excuse me for writing something silly,
the actual video parameters for all the tests are :
audio : 48 Khz 1536 Kbps LPCM
I'm sorry again.

Gorf · Post by **Gorf** » Thu Sep 08, 2005 4:23 pm

Can't help with the inability to generate the right filesize (given a CBR bitrate) but I can tell you that using PCM audio with those sort of video bitrates will cause a problem.

If you use AC3 2.0 at 192kbps or higher (some reccomend 224, but I can't tell the difference with 192) and a video bitrate of 6mbps, you'll have more space on the disc, it will be more compatible, and you'll see and hear no difference.

In fact, you should try your tests above at the lower video bitrate and see what comes out at the other end...

(Incidentally - the difference between the CBR and VBR bitrates above look to be in the 1500kbps region - are you sure you didn't have "video only" selected as your output?)

gigi10 · Post by **gigi10** » Thu Sep 08, 2005 5:13 pm

OK with you when you recommend bit rate 6000 and audio Ac3 192.
However, I've made another tests with encoding constant bit rate (CBR) :
the result is = when I encode to MPEG-2 with CBR over 6000 kbps, audio Ac3 or LPCM, the average bit rate of the MPEG file is always 6000.

Remember in my first message above :
USV8 : CBR 8264 kbps => MPEG file bit rate average 8251
MSP7 : CBR 8264 kbps => MPEG file bit rate average 6000

It seems the 2 codecs are different, or the same with different versions.
Perhaps it is important : I've got French versions of MSP7.3 and USV8.

What do you think about that ?