What's the top bitrate of S-VCD?

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From the profile for ligos, it looks like S-VCD goes at a VBR of 2320 tops (video) and avg 2200... that's not much and produces a somewhat blocky or grainy picture at the 480 x 480 resolution as far as I can see. Is that as high of a bitrate that the s-vcd standard allows?

-- Blackout (blackout@blackout.com), February 29, 2000


Blackout, given what LSX have said, where does LSX3 build 20 give SVCD presets, I think other posters here would like to know also, can you point me in the right direction please because I must have missed it.

The bbMPEG program sets 2600 as the limit and as posted that needs to be reduced to achieve multiplexing of sound and vision. Doug used 2500 and the auto setting in the bbMPEG went to 2376 and my test of that indicated a multiplexed file was produced at that rate.


-- Ross McL (rmclennan@esc.net.au), February 29, 2000.

Blackout, SVCD compatibility is not an "out of the box" feautre of LSX 3.0 build 20 (or any other build for that matter). Meaning it is not a preset. You have to aquire (don't know where) the SVCD for LSX profiles which will properly encode your video to SVCD specifications. Using the SVCD profiles in LSX will take all the guesswork out of the encoding as far as bitrate is concerned.

-- MrVCD (mrvcd@juno.com), March 01, 2000.

Blackout: I think one of the troubles with presets made by someone else out side the software maker is that one assumes they are totally compliant and are they? Consider the following:

The bbMPEG program presets for SVCD are different to the presets quoted and thats not to say you or either are actually wrong. What about Gops, P & I frames, pixel aspect ratio and all the other things that go to make up a correct mpeg2 file to comply with the SVCD spec? Perhaps getting some of that wrong may produce a non compliant file. One can perhaps assume that the factory might be more conservative but....... Blockiness may come simply from not having the correct pixel ratio setting in the preset or the screen not set correctly or the video card not coping.

Beware of VBR: LSX in its VBR MPEG2 presets state that the average bit rate is to be half the maximum value and if you try to encode with that not complied with it will tell you "it may not work in all players". It gives the option to continue so I would suggest that LSX might officially have a peak of 2600 (the maximum allowed) and an average of half that, 1300, but who knows they have not yet come out with anything on SVCD and I am sure would be disturbed to see people using their name as the source for the preset.

Most of the guys posting on this site are using CBR and it would be interesting to compare VBR with CBR at what are relatively low data rates. As I said above bbMPEG sets a CBR of 2376 as being acceptable and it certainly achieves correct multiplexing where as the higher rate of 2600 failed to multiplex correctly and may stop a DVD player from actually playing the file, Doug certainly failed at 2600 in a 525 and had to drop back.

-- Ross McL (rmclennan@esc.net.au), March 01, 2000.

I was wrong about bbMPEG setting a CBR, it apparently is a VBR average so that begs the question what should one do in LSX with its requirement that the average be half the maximum. Does that mean 4000+ as the peak for SVCD for an average of 2000+ or do you leave it at the default 6000 peak and select any old average?

Finally got bbMEPEG to do a great encode - that program is tops.

-- Ross McL (rmclennan@esc.net.au), March 02, 2000.

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