Bitrate question at DVinfo.net

Natalia Robba · June 9th, 2009, 01:18 AM

Hi guys,

I have a quick question.
I dont really understand much about video encoding.
I have 2 hours worth of northern lights footage from canada. Used my XH A1 camera. Footage is ok in that its been able to capture the lights pretty well, theres lots of noise but I was sort of expecting that.

My question is, the M2t files are huge, I've been playing around with Alive HD converter and am stumped as to what settings to use.
Ive been playing around with settings to see filesize and have found lowest file size is obtained when using a lower bitrate like 2000, my questions is...what sort of a difference does bitrate make with such dark noisy footage.

I can't actually make out a difference between 1280 x 720 @ 8000bitrate and 720 x 480 @ bitrate 2000.

Could someone give me some advice? I want to retain as much quality as possible while keeping filesize fairly low.

Thanks!

Bill Ravens · June 9th, 2009, 06:32 AM

My I make the following suggestion:
There's a number of ways to reduce the black threshhold noise in your footage. IMHO, the best way would be to transcode your footage to Cineform DI. Once done, you can use FirstLight to drop the shadow level until the noise is all but gone, without dmaging the "good" pixels in your footage.

Natalia Robba · June 25th, 2009, 05:04 AM

Hi Bill,

Thanks very much for your reply. However I'm not sure how to transcode to Cineform DI could you give me a little more info? I can't find anything about firstlight either on google :S

sorry!

Thanks!
Natalia

June 9th, 2009, 01:18 AM	#1
Natalia Robba New Boot Join Date: Feb 2008 Location: Gibraltar Posts: 14	Bitrate question Hi guys, I have a quick question. I dont really understand much about video encoding. I have 2 hours worth of northern lights footage from canada. Used my XH A1 camera. Footage is ok in that its been able to capture the lights pretty well, theres lots of noise but I was sort of expecting that. My question is, the M2t files are huge, I've been playing around with Alive HD converter and am stumped as to what settings to use. Ive been playing around with settings to see filesize and have found lowest file size is obtained when using a lower bitrate like 2000, my questions is...what sort of a difference does bitrate make with such dark noisy footage. I can't actually make out a difference between 1280 x 720 @ 8000bitrate and 720 x 480 @ bitrate 2000. Could someone give me some advice? I want to retain as much quality as possible while keeping filesize fairly low. Thanks!

June 9th, 2009, 06:32 AM	#2
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	My I make the following suggestion: There's a number of ways to reduce the black threshhold noise in your footage. IMHO, the best way would be to transcode your footage to Cineform DI. Once done, you can use FirstLight to drop the shadow level until the noise is all but gone, without dmaging the "good" pixels in your footage.

June 25th, 2009, 05:04 AM	#3
Natalia Robba New Boot Join Date: Feb 2008 Location: Gibraltar Posts: 14	Hi Bill, Thanks very much for your reply. However I'm not sure how to transcode to Cineform DI could you give me a little more info? I can't find anything about firstlight either on google :S sorry! Thanks! Natalia