S-VCD and Semi-CBR

[Daniele-Esposito]

TMPGEnc 2.02

***VIDEO***
Stream Type: MPEG-2
Size: 480x576 Pixels
Aspect Ratio: 4:3
Frame Rate: 25 Fps
Rate Control Mode: CBR, RT_CBR 2600 KBit/s
VBV Buffer Size: 0 (Automatic)
Profile & Level: Main Profile, Main Level
Video Format: PAL
Encode Mode: Non Interlaced (Progressive)
YUV Format: 4:2:0
DC Component Precision: 10 Bits
Motion Search Precision: Highest Quality (Very Slow)

***AUDIO***
Stream Type: MPEG-1 Layer 2
Sampling Frequency: 44.100 Hz
Channel Mode: Dual Channel
BitRate: 384 Kb/S
Error Protection: Yes
Enphasis: None

***SYSTEM STREAM***
System Stream Settings: MPEG-2 Super VideoCd (VBR)

1) Why my "Samsung DVD-611" standalone player play S-VCD choppy? I have used the settings now writed.
2) I know that S-VCD can use a maximum bitrate of 2600 Kb/s. But, if I try to create an MPEG-2 stream using CBR or RT_CBR in TMPGEnc, the bitrate change every second to 2592, 2601, 2604, 2590. It's not REALLY fixed to 2600!!! It's that normal? Can I set the bitrate to 2600? I would not use VBR :->.
3) Can I put MPEG-1 Layer 3 (.mp3) audio, instead of MPEG 1 Layer 1 or 2?

Thanks VERY much for your help!!!
Bye and merry Christmas.

Daniele Esposito (Italy).

[adam]

Yes this is normal. The term constant bitrate (CBR) is really a misnomer. A more accurate name would be controlled bitrate, because when you are encoding in cbr mode then the bitrate does still fluctuate slightly. I think you will find you can only achieve true cbr by encoding in vbr with all settings equal ie: min 2600kbits, avg 2600kbits, max 2600 kbits.

If I were you I would note exactly where the choppy parts are, assuming they are the same each time. Then use a bitrate calculator to check if your bitrate is peaking too high at those parts. If this is the case then I would lower the bitrate some. You should also realize that just because the standard supports upto 2600kbits that doesnt mean your dvd player will. Also total bitrate you can have (video + audio) cannot exceed ~2800kbits or so. You cannot use 2600kbits for video and 384kbits for audio and still be compliant, you have to lower one or the other.

No you cannot use mp3. Vcds and Svcds both use mpeg1 audio layer II.