Does HDV compress to MPEG2 on the tape?

[Rudyard]

I have been reading about camcorders like crazy the last few weeks as I am about to buy one. The general consensus (sp) is avoid hard disk drives and mini DVD's as they capture to compressed MPEG2 which isnt as good for editing as it is already compressed.

I understand Mini DV records at 25mbs and transfers as DV AVI - you do your stuff and then compress final video to MPEG2 - Which should equal better quality.

If that is correct, I found this part of the review of the new Sony HC3 HDV camcorder interesting as I was about to blow my budget right out and buy it.

From camcorderinfo.com

'Compression (7.0)
The HDR-HC3 uses the same date rate as SD MiniDV, 25Mbps. It is 1080 interlaced video with 60 fields per second. HDV must be compressed into an MPEG2 format to fit on the MiniDV tape.'

So to make HDV fit on normal miniDV tape they compress on the fly to MPEG2 - just like miniDVD and HDD camcorders and as such will lose quality when editing and recompressing to what will be HD DVD in the future?

Is this correct or am I missing something?

Also some other questions about this model if anyone knows are:

Does this camera not shoot in true widescreen, which if true I cant believe as all high def screens are all widescreen (for tv purposes that I know of). The quote below leads me to think it just crops and zooms a 4:3 image. Again I hope I am misunderstanding something.

'The HDR-HC3 features a single 4:3 aspect ratio CMOS chip. This is a CMOS chip different in aspect and type from the one featured on the HDR-FX1, Sony’s second most expensive HDV camcorder. The HDR-FX1 features three, native 16:9 CCDs'

'SteadyShot - This camcorder does include a SteadyShot function, which is intended to compensate for the handshake that becomes noticeable with higher zoom levels. Unfortunately, the SteadyShot feature is an electronic image stabilization system instead of the more accurate, less compromised optical image stabilization found on camcorders in this price range by manufacturers like Panasonic. '

Does electronic image stabillisation affect the quality of the video? Will it be noticeable? I dont understand exactly how it digitally changes my video.


Thankyou for any help.

[aedipuss]

the hc3 will record HD mpeg2 at 25mbps, otherwise what you would get is standard dv avi 720x480. not the same thing as mindvd or cam hd 720x480 30fps. it's a technical tape speed limitation not anything good/bad.

yes that one sounds like it crops 4:3 to 16:9. if that bothers you buy one of the other hdr cams that doesn't. depends on your display what would be best for you. most people will re-encode to dvd spec anyway, as HD mpegs aren't, and can't be burnt to dvdr. the loss from this cam's cropping will not be noticable if transcoded to dvd spec.

steady shot stabilizes the image, and is useful for handheld situations. you don't even notice it if implemented correctly. sonys tend to be very good at it. for fast pans or tripod work it should be turned off anyway.

[edDV]

I have been reading about camcorders like crazy the last few weeks as I am about to buy one. The general consensus (sp) is avoid hard disk drives and mini DVD's as they capture to compressed MPEG2 which isnt as good for editing as it is already compressed.

I understand Mini DV records at 25mbs and transfers as DV AVI - you do your stuff and then compress final video to MPEG2 - Which should equal better quality.

DV format maintains separate frames so editing is ideal. Each frame is compressed about 5x vs 16-40x for MPeg2 SD camcorders.

If that is correct, I found this part of the review of the new Sony HC3 HDV camcorder interesting as I was about to blow my budget right out and buy it.

From camcorderinfo.com

'Compression (7.0)
The HDR-HC3 uses the same date rate as SD MiniDV, 25Mbps. It is 1080 interlaced video with 60 fields per second. HDV must be compressed into an MPEG2 format to fit on the MiniDV tape.'

So to make HDV fit on normal miniDV tape they compress on the fly to MPEG2 - just like miniDVD and HDD camcorders and as such will lose quality when editing and recompressing to what will be HD DVD in the future?

Is this correct or am I missing something?

HDV records 1440x1080i* and does the horizontal stretch widescreen thing (similar to DV widescreen) on playback to get output to 1920x1080. At 25Mb/s the datarate is similar to HD/BD DVD but at 1440x1080/29.97 interlaced vs. 1920x1080p/23.976 for most HD DVD movies. HD/BD accepts other sizes as well.

Also some other questions about this model if anyone knows are:

Does this camera not shoot in true widescreen, which if true I cant believe as all high def screens are all widescreen (for tv purposes that I know of). The quote below leads me to think it just crops and zooms a 4:3 image. Again I hope I am misunderstanding something.

All 1080i is widescreen, HDV just stretches (scales) 1440 to 1920 during playback.

To edit the HDV, MPeg2 interframe compression needs to be reversed but that is accommodated in the format and editing software. You just need much more tmp file space as the 1440x1080 MPeg2 is decompressed for filters and effects. A faster processor will help deal with filtering the 4.5x number of pixels.

As said above, compression is in the same ballpark as HD/BD DVD but considerably more compressed than broadcast camcorders (e.g. 35Mb/s for XDCAM, 100Mb/s for DVCProHD, 144Mb/s for HDCAM and 440-880Mb/s for HDCAM-SR). You pay your money and take your choice.

'The HDR-HC3 features a single 4:3 aspect ratio CMOS chip. This is a CMOS chip different in aspect and type from the one featured on the HDR-FX1, Sony’s second most expensive HDV camcorder. The HDR-FX1 features three, native 16:9 CCDs'

'SteadyShot - This camcorder does include a SteadyShot function, which is intended to compensate for the handshake that becomes noticeable with higher zoom levels. Unfortunately, the SteadyShot feature is an electronic image stabilization system instead of the more accurate, less compromised optical image stabilization found on camcorders in this price range by manufacturers like Panasonic. '

Does electronic image stabillisation affect the quality of the video? Will it be noticeable? I dont understand exactly how it digitally changes my video.

Thankyou for any help.

Electronic stabilization filters the pixels, optical uses lens deformation and fixed pixels.

The 3CCD HDR-FX1 is a considerably larger camcorder and costs near double. The HC1 or HC3 are much smaller and more likely to be used.


*HDV as a format also supports 1280x720p but not that particular camcorder. BTW, don't be concerned about 1440x1080. HDCAM is also 1440x1080 and DVCProHD uses 1280x1080.