Is 48 kHz audio ok for SVCD?

[johnells]

I ask because all I can find is the following requirement: 32 - 384 kbit/sec MPEG-1 Layer2.

It does not mention frequencies. Like 32, 44.1, or 48 khz. Since the audio tracks (PCM stereo) I am ripping are 48 kHz I would like to leave them at that frequency and just encode the MPEG-1 Layer 2 file, rather than downsample to 44 kHz. I know my amp supports 32, 44.1 and 48 PCM, DD and DTS.

Can I do that? I know PC's don't like to output 48 kHz but I don't care as my DVD player/amp will be processing the sound.

John

[adam]

No, technically it is not ok. VCDs and SVCDs only support 44100kHz audio. If you use 48kHz then your disk will be non-compliant and there is no guarantee that it will play on any given SVCD compatible dvd player.

Most dvd players actually don't have problems with 48kHz audio, either in a VCD or SVCD. Use 48kHz at your own risk but the quality difference is minimal so you are really only saving yourself a little bit of time and effort. In my opinion its better to be safe then sorry, because even if your current dvd player supports 48kHz SVCDs, there is no guarantee that your next one will.

[johnells]

Adam, could you point me to your source? I just can't seem to find it documented anywhere.

John

[johnells]

Can anyone point me to a reference on the SVCD audio specifications? I have yet to find any definitive information on the allowable sampling frequencies for SVCD. The bitrate I know already is 32 - 384 or 128 to 320 depending on who you talk to.

John

[johnells]

OK I just answered my own question. Here is the answer.

Audio: MPEG-1 layer II
Sampling: 44.1 KHz
Bit rate: from 32 to 384 Kbps
Audio channels: up to 2 stereo or 4 mono
Surround sound: MPEG-2 ( 5+1 ) extension

Bit Rate may vary from frame to frame
Single channel mode: 32 to 192 Kbps
Dual channel mode: 64 to 384 Kbps
Stereo mode: 64 to 384 Kbps

Here is a link to a PDF white paper. Get it while it lasts.

http://www.licensing.philips.com/includes/download.php?id=2698&filename=2450.pdf

[RoopeT]

Actually it's better not to convert to 44.1 kHz. Has anybody actually ever heard of a DVD player (not SVCD player) having problems with 48 kHz audio? If you don't convert audio you can burn onto a DVD later (without having to canvert the audio again)

[adam]

Yes RoopeT I have heard of many dvd players which cannot play 48kHz audio. There was a pretty decent list at one point in a thread on isonews where a group accidentally forgot to downsample and at least two dozen people reported problems with audio playback. The problems went away after the repack.

Most dvd players have no problems with 48kHz audio in a VCD or SVCD, but the fact remains that if you don't follow the specs then there is no guarantee that your disk will play correctly.

[MOVIEGEEK]

The majority of DVD players(including my Toshiba & Mintek) do NOT support 48khz CD's.Just look at the DVD Player specs. for miniDVD support:https://www.videohelp.com/dvdplayers

[adam]

How are you determing that most dvd players don't support 48kHz audio MOVIEGEEK? The compatibility chart doesn't track supported audio frequencies. The only place where there is any input is in the user comments and I don't see too many reports on this issue. Also I'm not sure what minDVDs have to do with an XVCD or XSVCD with 48kHz audio.

From my own personal tests, which just consists of me going to Best Buy/Circuit City with a bunch of test disks, most DVD players don't seem to have any problem with 48kHz in an otherwise standard (S)VCD, but occasionally some do.

[MOVIEGEEK]

I am basing my assumption on my DVD players,when I insert a VCD with 48khz audio my players report "DVD Video" and the video plays with no audio.This is from DVDhelp miniDVD compatibility:

BTW adam...did you actually see and hear your disks on TV at BestBuy/Circuit City or are you basing your test on seeing "Play" on the display?

[adam]

Again, I fail to see how lack of support for MiniDVDs has anything to do with support for 48kHz audio in a VCD or SVCD. If you were to downsample a MiniDVD to 44100kHz it still wouldn't play in 95% of all DVD players. Support for MiniDVDs isn't lacking because of the audio frequency, its lacking because it is a totally hybrid format that does not come close to conforming to any supported standard that a dvd player supports. You cannot stick a vob file burnt in UDF file format on a cdr and expect it to be widely supported. You can, however, use a higher frequency in an otherwise supported format such as VCD and SVCD and still have proper playback, most of the time anyway.

I think maybe you are assuming that since your dvd player reports the disk as being "DVD Video" that this makes your disk a MiniDVD? This isn't the case at all, a MiniDVD is far more non-standard than a VCD with 48kHz audio sound. They are completely different formats.

I don't doubt that your two dvd players have playback problems with 48kHZ audio in a VCD or SVCD. like I said, many players do have problems with this, however 2 players does not constitute a majority.

Yes I only test players that are hooked up to tv with some form of audio output. Again, just from my personal tests, the majority of dvd players do support 48kHz audio in both VCDs and SVCDs, and the vast majority of DVD players do not support MiniDVDs at all.

SatStorm also recieved alot of reports from people regarding his CVD descriptions, or more specifically his suggestion to use 48kHz audio and make a non-standard CVD so that it could be more easily converted to DVD later on. He would have to confirm this but I believe that, even though many people complained that 48kHz audio wouldn't work in their CVDs, many more people reported that it worked just fine.