Mbps rates

[Alan Melville]

Hi All,

Can anyone explain the difference of a tape based system, such as our XL2's etc and the newer Mbps system.

Is there any tie in with lines per frame as with a tape based system?

I've noticed with the likes of a GoPro and video on consumer cameras if panning the video is not smooth, almost as if the pan speed doesn't sync with the recording speed and I'm assuming this has to do with the bit rate at which the the video is being recorded.

Is that correct?

Thanks,
Al

[Eric Olson]

Originally Posted by Alan Melville

I've noticed with the likes of a GoPro and video on consumer cameras if panning the video is not smooth, almost as if the pan speed doesn't sync with the recording speed and I'm assuming this has to do with the bit rate at which the the video is being recorded.

If the panning is not smooth, this usually means your computer is too old and slow to play AVCHD video.

[Alan Melville]

Hi Eric,

Thanks for the reply.

I had wondered about that but the computer is just under 2 years old and when I edit my tapes through the tape editor on it, then run the resulting file, I have no issues. However if I transfer the GoPro footage or footage from various consumer cameras to the HD of the computer (from SDHC cards) I still have issues with artifacting whilst panning or, for instance, a flower blowing in the wind. The movement is very erratic, almost a seriers of frames laced together, unlike the tape based file which is as smooth as a babies bum!

BUT, maybe the computer is a little old, although it's a reasonably high spec'd Toshiba Satellite.

Al

[Eric Olson]

Originally Posted by Alan Melville

Hi Eric,

Thanks for the reply.

I had wondered about that but the computer is just under 2 years old and when I edit my tapes through the tape editor on it, then run the resulting file, I have no issues. However if I transfer the GoPro footage or footage from various consumer cameras to the HD of the computer (from SDHC cards) I still have issues with artifacting whilst panning or, for instance, a flower blowing in the wind. The movement is very erratic, almost a seriers of frames laced together, unlike the tape based file which is as smooth as a babies bum!

BUT, maybe the computer is a little old, although it's a reasonably high spec'd Toshiba Satellite.

Al

It sounds like you are using a notebook computer. Try vacuuming the dust out of the tiny ventilation holes on the sides and bottom of the notebook. When a CPU overheats the hardware automatically slows down to protect itself. This might cause erratic movement in a video.

[Alan Melville]

Hi Eric,

Tried that, no difference. :(

Al

[Chris Soucy]

Hi, Alan............

Not sure what you are referring to when you say "tape based" - DV? HDV? Not that it really matters.

AVCHD has quite a reputation for being a difficult codec to work with, it being quite a bit more processor intensive than either of the other mentioned codecs.

That aside, panning causes the bit rate of all those codecs to rapidly head towards saturation, leading to the dreaded HDV "smear", not quite sure what the AVCHD equivalent is.

Given the limited upgradeability of notebooks, about the only avenue you might have could be to take the memory to the max, if it isn't there already, it certainly sounds like it's struggling at high bandwidths with that codec (AVCHD).


CS

[Alan Melville]

Thanks Chris,

I'll do some comparasions on a desk top. What you're saying makes sense.

Al

PS It's quite likely a high end gaming laptop would handle the graphics, out of interest I'll try it on a nephews laptop as well.

[Don Palomaki]

Most tape-based formats (e.g., DV, HDV) are much less demanding on the processor than AVCHD and will often playback more smoothly. Often you can improve playback and editing sped by recoding the AVCHD to another codec.

Generally video editing works best if the video is on a separate physical drive from the operating system and software. Similarly, if a computer is a bit short of RAM it can make playback look poor.

Slow frame rates can make pans and other camera moves look stuttery.

Fragmented and slow drives (less than 7200 RPM) can make playback uneven.

[Alan Melville]

Don,

Sorry for the late reply. :)

Thanks for your answer and info, one is always learning!

The laptop I use has a bit of grunt but maybe because of the fact I have everything in the same packet, so's to speak, and not a seperate drive, may be an issue + the drive speed.

My computer specs are;

CPU Intel Core i7 processor 720QM (1.6GHz/2.8GHz, 1333MHz FSB, 6MB L2 Cache)
Operating System Genuine Windows 7 Home Ultimate 64bit)
Screen Size 18.4" Widescreen HD+ TruBrite Display (1680 x 945), supports 720p
Memory 4GB DDR3 (2GB + 2GB) (1066MHz) expanded to 8GB

Storage 1000GB (500GB + 500GB) (5400rpm) SATA ..........and herein lays the problem maybe......

Graphics NVIDIA GeForce GT 330M (2270MB Total: 1GB discrete memory + 1246MB shared memory)
Optical Disc Drive Blu-Ray RW/DVD SuperMulti Double/Dual Layer Drive
Speakers Premium harman/kardon speakers
Sound Harman/Kardon Speakers

Cheers,
Al

[Don Palomaki]

I agree, the drive is likely the weak link for editing - single 5400 RPM coupled with being partitioned. You might try see if it behaves better if the video files are on a high speed SDHC or CF card on a high speed port (at least USB2) rather than on the local drive.

[Alan Melville]

Thanks Don,

I'll give it a go! I've not had a place, i.e. a house, to have a dedicated tower for editing but I now do, so I'll likely build up a dedicated desktop for editing. I'll do some research on it. I want to learn how to use Lightworks so I'll build around it.

Input welcome! :)

Cheers,
Al

[Eric Olson]

Originally Posted by Alan Melville

CPU Intel Core i7 processor 720QM (1.6GHz/2.8GHz, 1333MHz FSB, 6MB L2 Cache)
Operating System Genuine Windows 7 Home Ultimate 64bit)
Screen Size 18.4" Widescreen HD+ TruBrite Display (1680 x 945), supports 720p
Memory 4GB DDR3 (2GB + 2GB) (1066MHz) expanded to 8GB
Storage 1000GB (500GB + 500GB) (5400rpm) SATA ..........and herein lays the problem maybe......
Graphics NVIDIA GeForce GT 330M (2270MB Total: 1GB discrete memory + 1246MB shared memory)
Optical Disc Drive Blu-Ray RW/DVD SuperMulti Double/Dual Layer Drive
Speakers Premium harman/kardon speakers
Sound Harman/Kardon Speakers

It seems like a powerful enough system. Have you tried updating or installing the manufacturer's graphics and sound drivers?

[Alan Melville]

Hi Eric,

No I haven't but I will as I see no harm in try-ing, although upgrades may not be available any longer as the model is outdated.

Maybe it'll give me an excuse for buying an El Whizzo desk top unit..... :)

Cheers for that.

Al