what bit rate differential makes a noticeable difference?

[defense]

I'm just curious what bit rate differential you would notice a difference in the quality of a movie. I am new to this all, but I've just ripped a couple of movies onto 2 SVCD'S, both filling about 800 MB's each. The sound and picture quality is not that far off from the actual DVD, which I am very shocked to believe! The thing is that I ripped/encoded one movie at about 2100 kbps, another at 1720 kbps, and the last at 1666 kpbs. I have looked at all three closely, and believe it or not, there isn't a NOTICEABLE difference. When I watch any of the three on my dvd rom, I don't get excellent quality, but when I watch any of the three in my standalone player, I get basically the exact same quality. Can any of this be explained? I thought the lower the bitrate, the more you could fit on a CD, but the lower the quality. I am trying to avoid more then two SVCD's, and so far, two has been great. I really want to know what would happen if I tried to burn a movie on "ONE" CD-R. The bitrate would be around 720-800, would I have a noticeable difference then? And if so, would that bitrate yield results better then VHS at least? If so, it would be worth it.

Any help on this would be used and is definitely needed so I don't have to take 14 hours testing that bitrate.

[Craig Tucker]

You would certainly notice it with that low a bitrate, its less than half of your minimum setting. Beauty is in the eye of the beholder, as the saying goes. If it looks ok to you then fine, other people who viewed it may disagree. Some people have a more discerning eye than others, I have played VCD's to friends who thought it was a DVD. What size TV are you viewing it on, you may find the difference more noticable on a larger TV set.

[defense]

Craig, thanks for the info, it will be helpful. I have a 36' T.V. I understand with a bit rate that low it would probably be a bad picture. I am just trying to figure out why I still see almost exact "DVD" quality with 2100kbps, as I do with 1600ish. Shouldn't the difference between those two be immense? I don't mind VHS quality with "certain" movies that are not action packed, but are maybe of a comedy type. The comedies I would like to put on one cd, but the bit rate would be at around 700ish. Using DVD2SVCD, it gives you the option of an Mpeg-1 output or Mpeg-2. If I check Mpeg-2, and have a bitrate of 700ish, would it be VHS quality? Basically, what i'm thinking is if I use one CD-R, maybe I should just change the output to Mpeg-1 (VCD). Would that make sense? If the bitrate is that low, what would be the difference between Mpeg-1 and Mpeg-2? thanks again for your help on this.

[snowmoon]

defense:

Encoders keep getting better, so that might account for some of it. Most movies are ~4-6mbps CCIR 720x480. First you are going to SVCD that requires a 480x480 or 1/3 as much video data. Now lets take your video and letterbox it for 4:3 loosing another 1/4 of the video data so we end up with 50% less video to encode in the first place. So if a DVD runs 4-6mbps on average a SVCD can easly be done on 2-3mbps on average. Hmm SVCD tops out at 2.6, but that's ok reducing the bitrate further will hurt the video, but only on high end displays.

So as you can see 1.666mbps is only a reduction in the video to bitrate ratio of ~1/6 and with modern encoders it is more and more difficult to pick out reductions like that. A resuction to 700-800 though will likley produce signifigant artifacts unless the video to bitrate ratio is compinsated for by moving to CVD resolutions.

Cheers

[defense]

Snowmoon, thanks for your reply, I will have to print that out and read it over about twenty times to start to understand it. I think I actually understand the main point which is that It does make sense for me to be able to get that quality with SVCD. thank you for your response, it will be very helpful in understanding other aspects of DVD to SVCd.