My new Panasonic WJ-AVE5 Video Mixer
Bill Cherry
>Dissolves, wipes, and cuts between the sources are very clean. By
>disconnecting the respective sources there was no image jump. So I
>figured out that this means both sources are synced to an internal oscillator
>- the same one that drives the background color and black/white for
>fades. Further experiment with jittery tapes demonstrated its time
>base correction function. However, I haven't looked at the output on
>a scope. So I don't know if it does ALL the functions of a good TBC,
>like properly setting video levels, substituting a stable burst, and
>controlling the subcarrier to horizontal phase timing.
I hope Mark doesn't mind me adding to his postings. The
information might be interesting to others.
The input process of each of the two digital channels runs
asynchronously at it's own rate. How well each channel decodes
it's input and converts it to YUV digital values, depends on the
input lock, and the quality of the signal fed to it. The
output process, mix, wipe, and down stream functions (luminance
key, background gen., fader) all run synchronously at a rate
controlled by the internal sync generator (crystal controlled).
The burst stability, SCH relationship, digital to S-video encoding,
are all controlled by this sync & chroma reference generator.
Bill Cherry
Hewlett Packard Co.
Fort Collins, CO
Bill Cherry
>Learned something else interesting. When you hook up a key camera,
>IT becomes the reference for internal sync for your VCR inputs (busses
>A and B). Whenever I shut off or disconnected the key camera, the image
>jumped or rolled momentarily. Then another revelation: I played a
>tape that had a few jittery spots in the original recording and the
>combination of the AVE5 with key (reference) camera attached actually
>reduced the jitter! So the AVE5 acts like a TBC as well.
When a keying camera is attached, the AVE5 locks it's internal
sync generator (to which the output process of the two digital
channels is locked), to the sync of the keying camera, thus a stable
video signal should be used at this input. The lock is a sync
lock only (no chroma lock).
>I also noticed that digital effects (still, paint, mosaic) due show
>a degree of aliasing. I use still frame momentarily in wipes or dissolves
>to the next shot, so I don't think it will be too noticeable.
The digital channels have a field store, vice a frame store,
hence aliasing on some things, especially the still.
>Anyway, my impression so far is - what a helluva machine for 1400 bucks!
Considering that people like Future Video want $625 for a plastic
box with a microprocessor & a few interface chips, a little microcode,
and membrane buttons, as well as $90 or so for a firmware upgrade;
I couldn't agree more with the above comment. I feel Panasonic is
providing excellent performance for the price.
Mark Goldberg
>I hope Mark doesn't mind me adding to his postings. The
>information might be interesting to others.
>
>The input process of each of the two digital channels runs
>asynchronously at it's own rate. How well each channel decodes
>it's input and converts it to YUV digital values, depends on the
>input lock, and the quality of the signal fed to it. The
>output process, mix, wipe, and down stream functions (luminance
>key, background gen., fader) all run synchronously at a rate
>controlled by the internal sync generator (crystal controlled).
>The burst stability, SCH relationship, digital to S-video encoding,
>are all controlled by this sync & chroma reference generator.
The above infomation is almost correct. In the United States, "YUV"
values are not used. That's the dsignation for color difference signals
with PAL and SECAM. Here the color diffrence signals are Y, R-Y, B-Y.
But in a unit like the WJWVE-5, internal processing is really by Y-C.
=========David Taylor Research Center (a US Navy lab) - Annapolis, MD==========
/|/| /||)|/ /~_/\| |\|)[~|)/~_ | "Everyone's entitled to MY opinion."
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"Poor is the man whose pleasure depends on the permission of another."-Madonna