interesting information on GOP sizing..re: blockiness of VCD

[bilestyle]

well i've been lookin around for a while to help the "blockiness" of mpeg-1 encoding from mpeg2enc.(I JUST found these settings so i need to still run tests to see the difference) here is what i found "For VCDs sensible values might be a minimum of 9 and a maximum of 15. For SVCD 6 and 18 would be good values. If you only want to play it back on SW player you can use other min-max values"

So maybe changing the GOP size settings in AfroPic(or whatever you choose to use, i think currently only AfroPic and MediaPipe give the options to change GOP sizes) will fix the transient blockiness that people seem to not be very happy about. If anyone runs tests i'd like to know if these settings help at all.

[qshartle]

Your idea Worked!

i tried a 1.5 min clip of a movie, One without 9, 15 and one with.
The one with looked extremely better. I will post my results when the whole movie is done. I am also aiming for 1 disc VCD's.

Qshartle

[pants]

qshartle,

your post is confusing, i think you left out some info, when you get a chance can you clarify what settings worked.

thanks

pants

[qshartle]

I did 2 encodes with mediapipe.
One of them I used the basic settings.
The other i used Bilestile's idea abou the GOP for vcd. Min 9 Max 15

It worked really well. Its quality is as good as FfmpegX.

I will post my results of testing this when the whole movie is done encoding.

qshartle

[bilestyle]

i knew mpeg2enc was capable of similiar and comparable quality for VCD/mpeg-1 as ffmpeg, i just had to find the right settings.. im readin like a madman to find more settings in mpeg2enc to play with. ill post any other results i get later.

i found this while lookin around as well, so MAYBE something to consider "Usually MPEG player software is much more flexible than the hardware built into DVD and VCD players. This flexibility allows for significantly better compression to be achieved for the same quality.
The trick is to generate video streams that use big video buffers (500KB or more)"

that remark coincides with the -V setting in mpeg2enc - with afropic it defaults to 230 (ill add the ability to control it in 0.4) So supposedly making the buffer bigger allows better quality, so i guess that will be somethin to tweak as well.

be certain if you append this setting in mediapipe to append the setting as well in mplex when joining audio and video. in mplex u would add the -b flag with whatever number you used in mediapipe next to the -V flag.

im not sure if the difference will be THAT significant (if even significant at all) but apparently the GOP size changing made a huge difference, so i'll keep huntin for info.

[Pendejus]

All this is really a good information.

I usually make VCD and CVD for standalone players from iMovie, and I would like to know the legal values for GOPs and Vide buffer for vcd, svcd and cvd so I can use this information to obtain a better quality but making standards cvd,cvd for my stand alone.

Is there any web site where I can find all the information for the standard vcd,cvd or svcd ?

Thank you

[rockinsage]

bilestyle,

Allowing use access to the video buffer is a good idea. Is it also possible to allow use to control more specifically where the 'split' occurs, when post processing a VCD to .bin/.cue to fit 2 CD's? I like to try to split between chapters at a logical point, instead of splitting exactly 1/2 way through (which often makes an akward split). Would it be possible for the user to tweak where the split occurs?

thanks,
rockinsage

[SCB]

Pendejus, how do you go about making CVD's? Is there anything that makes them significantly better than SVCD's?

[Conquest10]

cvd are authored just like a svcd only at 352x480 instead of 480x480. 352x480 is actually half dvd resolution so i guess its more compatible with dvd than a svcd. svcd is a little shaper though.

[sterno]

CVD resolution is a legal DVD resolution (commonly called half-D1). That means that you wouldn't have to reencode the video to create a DVD later, just convert the audio. Some people are using CDs today because they're cheap and easy but plan to eventually put multiple CDs on one DVD when recordable DVD gets cheaper.

CVD sometimes works better with lower bitrates than SVCD because there's less image data to compress. If you have a high enough bitrate SVCD will probably look better because of the higher resolution. Some people say they can see differences, some people say they can't. It probably depends on your TV, your eyes, and the material.

[bilestyle]

bilestyle,

Allowing use access to the video buffer is a good idea. Is it also possible to allow use to control more specifically where the 'split' occurs, when post processing a VCD to .bin/.cue to fit 2 CD's? I like to try to split between chapters at a logical point, instead of splitting exactly 1/2 way through (which often makes an akward split). Would it be possible for the user to tweak where the split occurs?

thanks,
rockinsage

Well you CAN use the split feature in mplex (not currently though, i totally overlooked a bug that fell into place after i added post processing with bin/cue) so in the next version if you dont mind making the bin/cue yourself you can go back to setting where you want the split size. it would be a lot more difficult for me to code in the post processing to work after an mplex split, hence why i used mpgtx. Unfortunately from my knowledge of mpgtx it wouldnt be that simple for me to incorporate the user tweaking where the split is if they still desire to post process in vcdimager.

[pmcd]

CVD resolution is a legal DVD resolution (commonly called half-D1). That means that you wouldn't have to reencode the video to create a DVD later, just convert the audio. Some people are using CDs today because they're cheap and easy but plan to eventually put multiple CDs on one DVD when recordable DVD gets cheaper.

Does this mean that a DVD player that does not support SVCD will support CVD's ? Can they be put on ordinary CD-R's and still retain compatibility?

philip

[hardwork12]

pmcd

If the DVD player does not support SVCD it will most definitely not support CVD. Also just because a DVD player can support SVCD does not mean it will support CVD format. This relates to CVD and SCVD on standard CD-R.

Good question on if the CVD encoding put onto a DVD will that work in a standard DVD player that does not support CD-R CVD and SCVD encodings. I would like to know also.

ALL

I tried unsucessfully to take a captured video with 44.1Khz audio that works fine for CVD and encode this to Half D1 which uses 48Khz audio would like to know how this is done. I use vdub for capture and TMPGEnc for encoding.

[AntnyMD]

All players that support SVCD also support CVD, as SVCD is a sort of "container" for the CVD specification as well as the SVCD standard. There were some stand-alone CVD-only players made, and those are likely not to support the SVCD resolutions of 480x480/576.