MPEG encoded still pictures with _optional_ MPEG audio

[mzidanic]

The VCDImager documentation (manual.txt) states the following about Segment Play Items (SPI):

Segment Items
-------------

Segment items are stored in the so-called SPI area, which consists
of up to 1980 allocation units which are called "segments". Each
segment consists of 150 XA form 2 sectors. Thus the SPI area can
contain up to 658 MB of real-time data(1).

A segment (play) item is a MPEG stream stored in one or more
consecutive segments. A segment item can be
* MPEG video with _optional_ MPEG audio.

* MPEG encoded still pictures with _optional_ MPEG audio.

* MPEG audio only.(2)

I'd like to use a still picture with audio as a menu, accessible throught the PBC. If I use tmpgenc to encode a .bmp with an audio .wav file and generate a standard vcd-compliant mpeg-1, that's a big file with alot of wasted video bandwidth (1150 kbps worth) for a still frame. I could cut that down to 300 kbps video rate and get decent video, but that still doesn't seem very efficient. Is there a way to encode a still frame with audio into an mpeg-1 that only puts in a single video frame?

thanks,
mike

[mzidanic]

ok, i found a tutorial (www.geocities.com/mikk999/VCDStills.htm) that showed me how to do hi res stills with audio. The trick is to create two seperate mpg's, one for the still, one for the audio. The tutorial explains how to do with the Phillips VCDToolkit, but it can be done with tmpgenc as well. Here's some sample xml that does it:

<selection id="sel_still_r1">
<bsn>1</bsn>
<timeout ref="sel_r1"/>
<wait>0</wait>
<loop jump-timing="immediate">1</loop>
<play-item ref="seg_still_r1"/>
</selection>
<selection id="sel_r1">
<bsn>1</bsn>
<wait>0</wait>
<loop jump-timing="immediate">1</loop>
<play-item ref="seg_r1"/>

the first selection just displays the still, then the next "seg_r1" plays the audio-only mpg. Since there's no video in "seg_r1", the still remains displayed while the audio plays. Very cool.

Now just one more thing. I can't get tmpgenc to convert a .bmp to a "video-only" system stream. If I try, it pretends like it's encoding, but no .mpg shows up. So I've had to encode an audio+video system stream. It creates a .mpg, but it's got two audio frames in it. That's ok if you only have one menu, but I want to switch to a new menu still and a new audio after the first audio times out. With two empty audio frames in the still, I can hear a short pause or break in the audio as it goes from the 1st audio, to the 2nd still, then the 2nd audio. Bascially what I'm doing is playing a live album split up into tracks (audio-only mpgs) and changing the still pic as it goes from one track to the next (so you know which song is playing).

So how do you get an mpg with just a single still frame in it - no audio?