Talk:Super Video CD

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[edit] 5.1 surround

I thought the only method for encoding 5.1 surround sound on a S-VCD was with the MPEG Multichannel format? - Anon

  • I'm not sure of the details; my source was the VideoHelp.com SVCD page, which says that 5.1 is supported through an mpeg extension. This information is reflected in the article. Please feel free to clarify it if you know more about it! -- Wapcaplet 23:50, 1 Nov 2004 (UTC)
MPEG Multichannel is an extension to MPEG-2 Audio. It is backward compatible. Players that don't support it will play only 2 front channels and additional infromation will be discarded (not mixed). See MPEG Multichannel article for details. —Preceding unsigned comment added by 89.161.12.238 (talk) 20:49, 26 January 2008 (UTC)

I do not think that there is 5.1 surround sound on SVCD. SVCD was improvement on both image resolution and sound quality due to allowence of higher bitrate on mp2 (MPEG-1 Audio Layer-2). But mp2 do not support sound beyond stereo. 22:55, 18 March 2008

[edit] Resolution

I have some doubts about the SVCD resolutions.

  • Why does SVCD uses 480 lines if, for example, NTSC supports 525 ?
    • It's stretched to fit, but it also depends on the aspect ratio. That's why you sometimes see lines flicker.
  • How a 4:3 or 16:9 screen is supposed to use a 480x480 / 480x576 resolution, that is, the horizontal resolution lower than the vertical resolution (or, what are the horizontal resolutions of a TV) ?
    • The aspect ratio stretches the image (new_width = height*aspect_ratio, height stays the same) and then is rescaled again (zoomed while keeping new width and height proportional) to fit your screen so that the new width fills the screen (this is done in one step by your DVD player). If the height is less than 525 (16:9 ratio), it will fill the empty space with black bars. This is otherwise known as anamorphic. EX: Take a 480x480 SVCD with aspect ratio 4:3, the image will be rescaled to 480*4/3=640. So 640x480 is your image size. Aspect ratio of 16:9 gives 480*16/9 = 854, image size = 854x480.

--200.208.45.2 14:40, 8 Mar 2005 (UTC)

I'm afraid I don't know the technical details of how TVs work, but I know the info in this article is correct because I've worked with SVCDs a lot. According to the NTSC article, the extra scanlines (up to 525) in NTSC are used for sync, vertical retrace, and stuff like closed-captioning, but only 480 lines of picture are actually used (which is in keeping with the 480-pixel height of SVCD and DVD). PAL has more scanlines, and thus more vertical resolution (576 for SVCD and DVD), but a lower screen refresh rate.

At any rate, your question about aspect ratio: a TV can have those funky resolutions simply because the "pixels" in a TV are not square. The image (regardless of how many pixels it has) is just stretched to fit 4:3 or 16:9 (usually by the DVD player, but sometimes by the TV). I don't think standard (non hi-def) TV screens have a defined horizontal resolution; it's just a question of how many pixels you want to stuff in there. VCD resolution is only 352 pixels wide, while full-width DVD resolution is 720 pixels - more than twice as wide (and the difference is noticeable). I suspect that for most non-HDTVs, more than 720 pixels of width would be wasted. I've often seen normal NTSC TVs classified as 640x480 (which happens to also give you square pixels at a 4:3 aspect, making it nice for video production om a computer; computer monitor resolutions usually have ~1:1 pixels).

I hope that helped answer your questions! -- Wapcaplet 15:42, 8 Mar 2005 (UTC)

[edit] Article cleanup

I've made a first attempt at improving the narrative flow of the "Technical specifications" section. I brutally summarized a couple things; the Laserdisc comparison has been condensed to "...at a picture quality roughly comparable to Laserdisc."" The lengthy explanation of why MPEG Multichannel isn't practical was condensed to "...though space constraints and poor hardware support make it somewhat impractical." I removed the bit about why SVCD is tricky to convert to DVD (and how to hack around it), since I don't think it's relevant; I also removed the part about why DTS and Dolby Digital are unsupported. Comments welcome. -- Wapcaplet 16:02, 5 November 2005 (UTC)

[edit] DVD player compatibility

Whether or not a SVCD plays well, or at all, on a DVD player depends on if the MPEG decoding hardware is designed to properly support the format. Many models of DVD player made by APEX fully support SVCD- even if they don't have the official logo. I've never seen any of the display problems mentioned in this article on any DVD player I've tried an SVCD in, where the disc would play. Other players just wouldn't recognize the disc. There can't be an incompatibility in *vertical* resolution because DVD and SVCD use the same number of lines. —Preceding unsigned comment added by Bizzybody (talk • contribs) 06:25, 29 December 2007 (UTC)

Windows Movie Maker supports Standard Video CD format, but I am not quite sure if it supports the Super Video CD format. It could also depend on whever or not the computer is modern enouth or not to be able to compress files to the MPEG-2 format. About every computer there ever where can compress files to MPEG-1 format, in which case they can produce Standard Video CD's. Also Multie Region DVD players can play both Standard and Super Video CD formats. J2F Duck (talk) 13:37, 8 March 2008 (UTC)

[edit] VBR coding support in Super Video CD

"Super Video Compact Disc - A Technical Explanation" document, which is an official document describing the standard from Philips says: "The Audio streams are selectable by the user, and VBR coding is used for a more efficient compression". However some of the users disagree. So I want to know on what official documents they are basing their statements that SVCD only supports CBR coding. —Preceding unsigned comment added by 89.161.12.238 (talk) 19:22, 19 January 2008 (UTC)

That would be the ISO/IEC 11172-3 standard which defines MPEG-1 Audio Layer II, the audio format used for Super Video CD. The standard does not support VBR encoding. Empirical data also backs this up; try encoding an SVCD with a VBR MP2 audio stream and see how well it plays in a standalone: it won't. -- Y|yukichigai (ramble argue check) 22:54, 20 January 2008 (UTC)
Did a little digging: apparently you are correct, the SVCD spec does include support for VBR audio. However, it's also apparent that hardware support for that is somewhat spotty (much like multichannel 5.1 support) hence the confusion. I shall update the page accordingly. -- Y|yukichigai (ramble argue check) 23:11, 20 January 2008 (UTC)

[edit] Merge Video CD, Super Video CD and China Video Disc

I think that along with Super Video CD and China Video Disc, thses 3 articles should be merges as they are pretty much the same apart from the fact that they have differant resolutions on the screen, and differant compression files. Mergeing these 3 articles will be like uniteing a Hawker Hunter, it's Pilot and it's ground crew. J2F Duck (talk) 16:18, 8 March 2008 (UTC)

Any comments about merging CVD and SVCD should be on the CVD talk page, not here. Just click the "Discuss" link in the Merge Proposal box at the top of either article.
I don't agree about merging VCD with SVCD. They have nothing at all in common, other than the fact that they use CDs recorded in mode 2. MPEG-1 vs MPEG-2, CBR vs VBR. 240/288 lines vs 480/576 lines. Hard-coded vs text subtitles. Completely different development history. Completely different adoption. etc. You might as well propose merging the SVCD article with DVD, as they have just as much in common with each other. I've already merged several stubs (XSVCD, RSVCD, MVCD, KVCD, DVCD, etc.) into the VCD and SVCD articles, and I'm in the process of merging CVD and SVCD, but I can't see any reason at all to merge VCD with SVCD, and I don't think it's practically possible. Rcooley (talk) 18:31, 8 March 2008 (UTC)
I agree, VCD is vastly different than SVCD. (The latter is the successor to the first, as a matter of fact) Merging the two articles would make no sense since the formats have different origins, developers, compatibility, etc. etc. You'd essentially wind up with separate sections for each one which would wind up working like two separate articles anyway. SVCD and CVD, on the other hand, came into being out of the same drive, and given the very slight difference in format it makes sense to merge 'em. -- Y|yukichigai (ramble argue check) 20:43, 8 March 2008 (UTC)