Why SVCD and not CVD (352 x 480) that is DVD compatible.....

[amjm]

Why SVCD and not CVD (352 x 480) that is DVD compatible.
I still have to make the DVD test but I have made CVD just like if I would a SVCD but with 352 x 480 MPG2 and no more than 2500 bitrate and authore then as SVCD and have no problem.

I do have a DVD recorder but still need to make more CVD's to put more episodes of smallville on one DVDR.

I have tryed SVCD to DVDR and is verry difficult and some incompatibilities.

So if 352 x 480 at 2500 bitrate can be used for SVCD and DVD with no problem Why still use SVCD?
Thanks,

:P

[DJRumpy]

More people have CD Burners, rather than DVDBurners. I suspect that as DVD Burners become more commonplace, SVCD will slowly fall by the wayside. Owning a DVD Burner myself, SVCD is irritating, because it's not resolution compatible, and header trick doesn't work on all players. I stick to the rules when making DVD's. Currently I just re-encode them to full 720x480, but if they were CVD, I'd probably just resample the audio, and drop them on, as is.

When comparing apples to oranges, SVCD just has more market than CVD. CVD was created first, but SVCD had more backing power behind it when it was implemented. Most people are only willing to create, what their own players will play. CVD has less player support than SVCD.

DVD Burners will hopefully change all of that eventually...

Of the two, I prefer CVD, simply becuase it has lower bitrate demands than SVCD, and it can produce a smaller file.

[RabidDog]

So, If i create a cvd with 48000 khz sound when when I come to put projects onto DVD I should have virtually no problems.
(And my player can play cvd with 48khz!)

[spidey]

Yes, I believe so. It really depends on your authoring program and what it depends resolution-wise per stream (mpeg 1 0r 2)

I'd recommend de-multiplexing the streams though and also ac3'ing the 48 khz Mp2.

Check your documentation though on whichever dvd authroing program your using, I agree with DJ Rumpy's grumblings on them not accepting SVCD resolution. It is a giant pain in the ass to redo all the resolutions on SVCD clips, but unfortunatley due to most authoring programs not accepting 480 x 480 res m2v's it's necessary.

The fastest and least painful way I have found is taking an SVCD - demultiplexing it - ac3'ing the mp2 (after you've converted it to 48 Khz if it already isn't), and then frameserving the m2v via Avisynth into CCE - which'll resize it and re-encode it (based on your script) in about 45 minutes per 1.5 hours of Video.

[DJRumpy]

RabidDog, a CVD with 48Khz audio would be non-compliant. You could, however, create a CVD with 44.1Khz sound, and later demultiplex the audio, convert it to 48Khz, and multiplex it back in, in a very small amount of time, with not loss of Video quality.

Spidey's method is also my method of choice for converting, although I rarely mess with the audio, since the MPA (MP2) audio created by CCE can be converted to 48Khz during the re-encode. I've found that leaving the extension to MPA instead of MP2 gets rid of complaints by many authoring software apps that seem to accept only AC3 audio (Like SpruceUp).

[RabidDog]

just waiting for media & writers to reduce in price !
(I would pay about £140 and 50p for media, less if poss)

HAve to go on to tesco value line ...5p for large tin of beans
7p for a loaf of Bread.

I may not be pleasant to be near, but by god its cheap

[macleod]

DJRumpy, I am a little confused by your comment:

RabidDog, a CVD with 48Khz audio would be non-compliant. You could, however, create a CVD with 44.1Khz sound, and later demultiplex the audio, convert it to 48Khz, and multiplex it back in, in a very small amount of time, with not loss of Video quality.

A CVD with 48mhz audio would be non-compliant? I have been using DVD2SVCD to convert my dvd's to CVD using 48mhz compliance. From my readings and the reason for doing CVD with 48mhz audio is that when the file is later converted to DVD-R or DVD+R, it will be a quick and easy conversion to make it compliant for DVD? I hope that I am right because I have about 140 movies that were made CVD 48mhz so that it could be converted without resampling, etc. Where did you learn that CVD 48mhz is considered non-compliant?

[Vejita-sama]

He means that if you read the CVD standard it calls for 44.1khz audio, so if you make one with 48khz audio you're really making an xCVD.

In fact you can think of a CVD as an xSVCD at different resolution. In the end it's all MPEG2 encoded data. Bottomline if you're videos are:

Video - 720x480, 352x480 or 352x240 MPEG2
Audio - 48khz (mpeg1 layer II, or mpegII layer II, or ac3)

You are good to go when/if you get a DVDR burner. All you'll have to do is:

1) Convert SVCD to MPEG (eg. CDGear)
2) Demux MPEG to m2v + mpa files
3) Author DVD
4) Burn

aside - some authoring programs can load MPEG files but most require that you demux first. Remember thou that going from SVCD to DVD will not improve picture quaility. It will just allow you to store a LOT more data per disc and add menus/extras if you so desired.

[macleod]

Wow. Must of read the standard wrong then. Actually, I probably read it right, but figured, "d-uh" dont want to have to resample the audio so I'll keep it at 48mhz.

I am well aware of the "can't polish a turd" concept with converting from one format "up" to another. Cant remember who coined the phrase on this site (cant polish a turd), but I try to use it periodically in my meetings. Just strikes me as funny.

To go off the main topic hear, the close GOP's piece. I have read both on closing vs. not closing GOP's for later DVD compliance. Personally, I do not close GOP's when I do my CVD's. Hope it doesnt bite me in the ass when I go to DVD. Also, the debate over DVD-R and DVD+R. I know there is the difference between price of media and it has been debated a few times on the site, but it seems that the way to go is DVD-R from what I have seen.

[RabidDog]

yep the reason why I'm attracted to cvd with 48khz sound is that there is virtually no reconversion required to go to dvd. And of course my player will play the cdr. 8)

[DJRumpy]

If your DVD player supports CVD with 48Khz audio, and your not worried about compatability in other players, than definately leave your audio at 48Khz. Then it's only a matter of drag-n-drop into your DVD authoring software.

[DJRumpy]

On a side note, Vejita-sama makes an excellent point. The only thing that makes your CVD non-compliant is the fact that your calling it CVD. Otherwise, it's a fully DVD compliant MPEG-2.

I only mention the CVD standard, simply becuase you were not using the proper audio frequency, and many players that do support CVD could choke on your disk.

[RabidDog]

so, if i dont call it CVD then its compliant? DOH!!

[SaSi]

To go off the main topic hear, the close GOP's piece. I have read both on closing vs. not closing GOP's for later DVD compliance. Personally, I do not close GOP's when I do my CVD's. Hope it doesnt bite me in the ass when I go to DVD. Also, the debate over DVD-R and DVD+R. I know there is the difference between price of media and it has been debated a few times on the site, but it seems that the way to go is DVD-R from what I have seen.

On the GOP issue, if you want to be able to author DVDs with CVD or SVCD streams, GOP structure is critical.
Many people, including myself, don't bother with this aspect when creating SVCDs and create streams that have the wrong GOP structure (i.e. no GOP structure at all).

The DVD standard is that there must be a GOP length of 15 (that means that from I-frame to i-Frame you must have a maximum of 15 B and P frames (some programs accept more, but Scenarist and DVD fusion enforce the standard rigidly).

If you read the guide "Preparing DVD compliant MPEG-2 streams with Tmpgenc", you will see the settings for GOP. Use them as templates even for SVCD and you will be fine.

Closed GOPs help editing the MPEG-2 stream more easily, however are not recommended for final compression as the picture quality degrades slightly for a given bitrate.

48kHz MPEG-1 Layer II audio is fine for both SVCD and DVD, however some old players may have problems. I think(...) that DVD players that play MP3 will not have problems with sampling rate.

[vitualis]

48kHz MPEG-1 Layer II audio is fine for both SVCD and DVD, however some old players may have problems. I think(...) that DVD players that play MP3 will not have problems with sampling rate.

SVCD (and CVD) and VCD require the audio to be sampled at 44.1 kHz only for it to be compliant. Many players don't care but some don't play S/VCDs properly if the audio is not at the standard sampling rate.

Regards.

[DJRumpy]

Yup. If it isn't standard, your taking your chances.

As to GOP structure, your encoder will default to your standard GOP length (either for NTSC (15), or PAL (18) [ or the other way around..I always confuse the two. Somebody?... ]). You should have no need to mess with it if you haven't messed with it to begin with. The GOP length is the same for SVCD, CVD, VCD, and DVD. Moving from one format to the other should not be an issue unless someone muxed with the settings to begin with. Converting from PAL to NTSC and vice versa also isn't a problem, since the frame served file, or the AVI, is automatically re-encoded with the proper GOP length, according to your encoder's settings for NTSC or PAL.

Also, I believe the GOP length can be shorter than those values, just not greater than 15 or 18 (depending on where you are... ). Adam or Snowmoon, or Michael should know off the top of their head.

[SatStorm]

It is 15 for PAL and 18 for NTSC. When I first wrote the CVD guide, I had it opposite (my faulse, Virtualis corrected me) and many PAL users start closing the GOPS, so they end up with 16 GOP lenghts for PAL to make the authoring programs except the mpeg files.
That isn't neccessary if you set the PAL GOP structure 15 or less.

Also, the NTSC to PAL convertion is a very difficult proccess. It is in no way automatic! There is only one way for good results: Inverse Telecine with Vdub, save as avi, change the framerate from 23.97 to 25, change the audio and encode with TMPGenc as PAL. That way anything is a bit speed up (like 34rpm of a 33 1/3 LP record), but there is no flickering, statering, frame jump, etc, you may notice if you go any other way!

[DJRumpy]

There wasn't really a question of converting from PAL to NTSC. I just threw that in there in case they were wondering if the GOP length would affect a conversion from one format to another.

The actaul conversion from/to PAL & NTSC isn't all that complicated anymore. I always use AVISynth, and the AssumeFPS command. This method slows down or speeds up your AVI, so there are no dropped frames, making a very smooth conversion to or from 25fps and 23.976 fps. Essentially the same way the studios move an NTSC film to PAL format.

BeSweet GUI now comes with drop down selectable options to stretch/shrink you audio from one format to the other (NTSC <--> PAL), making the audio piece easy as well. The quality is excellent, with none of the chipmunk highs, or deep base lows, resulting from changing the audio speed.

[RabidDog]

I notice that on the kwag templates the gop structure is set to outlandish values like 2000+. I dont fully understand gop structures but this is amazing that any players tolerate this sort of structure.
Also IMHO its not that closing gops degrades the quality as such, it merely uses up more bits resulting in a slightly larger filesize..? (or a lower average bitrate for the same filesize).

[vitualis]

It should be noted that just because the GOP values are really long in kwag's templates doesn't necessarily mean that the length of the GOP is actually that long in the MPEG. The GOP value sets the MAXIMUM length. Depending on the material and MPEG encoder, it usually inserts a new I frame whenever it "thinks" it would be better to have one.

Having a closed GOP does theorectically reduce the quality of the video. Basically, it means that "temporal" compression (I mean compression between frames) cannot be performed BETWEEN GOPs (as can be done if you have open GOPs). I personally don't notice much of a difference, however.

Regards.

[kwag]

I notice that on the kwag templates the gop structure is set to outlandish values like 2000+.

Read Q-29 here: http://www.kvcd.net/forum/viewtopic.php?t=68

-kwag

[macleod]

Alright guys, y'all are making me feel stupid here

I was all thinking I am "billy bad ass" with all of my knowledge with encoding, ripping, converting and stuff and then y'all go an open up the floodgates and make me feel like a moron, LOL

Seriously, though I am sorta geting the felling that I am Ok with not having closed the GOP structure on my 140+ CVD's. If I didnt mention it, I used DVD2SVCD for the majority of my stuff. I have an apex 1100W and the thing plays everyone, but since I got my dvd burner, I'm know wanting to convert all my CVD's over to DVD-R for maximum compatibility with other DVD players. I have one dvd-rw and am planning on doing a test run this weekend.

[VidGuy]

As far as I know, you don't need closed GOP UNLESS you want to do multi-angle DVD, or you want to edit the mpg (closed GOP makes most editors work a LOT better).

Multi-Angle DVDs need to use closed GOP as well. Other than that, open GOP is fine.

[macleod]

That was just the answer I wanted to hear. I was starting to sweat a little thinking I may have to re-encode all of my DVD's. Looks like I am safe. Wahooo!!!

[DJRumpy]

The ONLY reason you would have to close them is for multi-angle. Otherwise, your taking a theorectical hit in quality by closing them. Don't worry about Editor compatability unless you have a problem (I never have. If I did, I would find another editor... ).

[SaSi]

Having open GOPs is allright, and most commercial DVDs are done this way. Of course, those having multiangle are having them closed, but I have never (yet ) seen one.

However, there is another aspect on the question "to close or not to close". When encoding with open GOPs, a P or B frame can reference a frame from a previous GOP. In addition, having chapter pointers in a DVD allows random access to a specific location (an I frame). If the player starts playback from such a point, it has to start with the I frame and continue with the ones in sequence.

If the following frames reference previous ones (before the chapter entry point), the DVD player does not have them in memory and there may be a problem.

I read a discussion on the subject and my understanding is that some DVD players will have a problem there by displaying green macroblocks on the frames that reference "never-played" frames.

I have tested this with my DVD player (a yamakawa 215) and I can't say I have noticed such a problem. The only thing I noticed is that in certain cases, the DVD starts playback, plays a single or more frames and then pauses for a moment to continue after this brief pause.

I suspect that the decoder scans back to obtain the missing frames during the pause. But of course this is mere speculation.

[macleod]

I posted this question on a new thread, but then I figured, d-uh, I should ask y'all.

What editor do you use that allows you to have the GOP's not closed. The reason I ask is that I have been trying to burn some movies this weekend onto DVD-R. I used ISOBUSTER to pull the mpeg's from the cd's (as I mentioned in earlier posts, I used DVD2SVCD, however didnt close GOP's) and then tried to author them in uldead dvd movie factory 1. I get a "The number of video frames in a GOP is not valid for a DVD" error message when I go to burn.

I've tried spruceup, but the import process stops at 10% and the video doesnt import.

DO you know of a GOP patcher or something or can recommend a not so finicky authorer???

[SaSi]

Don't confuse closed GOPs with their existence. SVCD doesn't force you to have GOPs and their headers. This means that SVCD encoders are not suitable for DVD compliant encoding.

On the other hand, it's good that DVD authoring s/w check for compatibility. Imagine burning DVDs and find they are not playable.

CCE, Tmpgenc and NewConcept are three encoders (first is best), that allow you to create DVD conformant streams.

They, also, allow you to "break" the DVD rules, if you need to (for other reasons). To make sure GOPs don't cause problems, use the DVD compliant or Standard presets. What you actually need is a GOP structure of 30 or less frames preceded by a header.