Analog capture (AD/DA) on Digital8 camera?

[plaxamate]

Hi all,

Long time lurker, first time poster.

I'm trying to determine if my Sony DCR-TRV240 has the ability to capture pure analog from my hi8 and 8mm (via the S-Video output) or if the camera does a AD/DA conversion. How would I find this information? I know I can use it as a "passthrough" device, but do not wish to capture my analog 8mm in DV. I've already copied all the DV that I have and am ready to capture the analog. Will this camera do this or would I need to switch to my regular 8mm camera (which, unfortunately, doesn't have S-video output)?

Thanks for any help!

[hodgey]

That depends what you mean by pure analog. If you mean whether it can play 8mm/Hi8 tapes and output them through S-Video, then that is supported.

It will digitize the signal internally for the DNR(Noise reduction) and TBC(Time base correction) functionality (Though I don't think it's DV-encoded, unless you use the firewire output). Not sure if it can be completely bypassed by turning off DNR and TBC, but I don't think so (you would have to dig through the service manual to be sure). Granted, you generally want the TBC to be enabled to get a much more stable image, the DNR function in the cameras isn't super useful.

Sending the video through a composite cable will most likely have more impact on the quality than whatever the D8 camera does (especially for Hi8 as it can't really carry the full bandwidth of the image data on a Hi8 cassette). How much depends on the rest of the capture setup, whether the devices that captures the composite signal does a good job at separating chroma and luma.

[plaxamate]

Thank you for the reply. I've attached the service manual to this reply. From what I can tell (granted, it's been over 25 years since I last read a schematic), it appears to bypass the A/D converter when using S-video. Does that sound correct? I cannot seem to follow the TBC line properly to determine that one.

[hodgey]

It's a bit hard to say, as the manual doesn't have a description of what occurs inside the ICs. The IC marked A/D converter seems to be involved in converting from the external video input to digital to be stored on D8 tape.

Is there any particular reason you want a signal that doesn't go through the A/D D/A process?

[plaxamate]

Thanks! I plan to capture using the S-video out for the 8 and Hi8 tapes. My understanding is that going through the converter forces the signal to digital and then re-converts that digital to analog. I just want to capture the original analog signal because I'm unsure what the a/d d/a conversion is doing to it. If it's converting it to DV and then back to analog, I could just firewire passthrough the signal, but I don't want to do it that way.

[hodgey]

I don't think it does any DV conversion on the S-Video output. Video captured from the DCR-240 will most likely look better, as you avoid having to use composite, and the TBC functionality of the camera(on by default) helps stabilize the unstable analog video signal coming off the tape. If you are in PAL land you may encounter issue with the far right edge being discoloured which may not happen on the older camera.

Of course, since you have both options, it should be simple enough to do a test yourself to see what you prefer.

[VideoTechMan]

The camera will only digitize the signal if its going to be captured via DV direct to the PC. If you are outputting the signal via the analog jacks, then it bypasses the DV conversion. I have the TRV-350 camera and does a great job of playing back the tapes to my editing system. And yes, don't use composite for whatever reason....S-Video only.

[plaxamate]

Great! This is exactly what I thought. Thanks!

[juhok]

My experience with TRV320 and TRV8000 -> s-video output does not go thru DV encoding and quality is better than DV output.

edit: And indeed these are PAL models with right edge V-channel damage. It's pretty easy to fix in Avisynth/Vapoursynth.