codec and bitrate setting for slomo

Dan Keaton · September 28th, 2010, 08:36 AM

Dear Friends,

We are trying to be honest and open when we report the reduced bit rate when cranking.

But, there is more to this than is obvious on first glance.

The reduced bit rate, is the actual target bit rate per second, and our message is accurate.

The actual bit rate per frame remains the same as the full requested bit-rate.

Thus, on a frame by frame basis, one gets the same bit-rate, but if there are one half the number of frames per second, then the "Bit-Rate per Second", is one half the normal requested bit-rate.

We force "I-Frame Only" when cranking is active.

When using our Over and Under-Cranking feature, if the Base Rate and the Crank Rate are the same, then the audio will be fine, both embedded and analog audio.

This is a nice tool, for some cameras, to obtain certain frame rates that are otherwise unsupported by the camera.

As always, I hope this helps.

Cees van Kempen · September 28th, 2010, 09:08 AM

Steve, as Dan describes Piotr is right. Since it will be I-Fo anyhow, quality wise it does not make any difference wheather I use overcrank or just shoot 60p. The latter however always gives sound and gives the opportunity to shoot 60p and in Cimema Tools bring it down to 25p. The 60 to 25 conversion is not able in overcrank in the nano (as in many devices there still is the NTSC vs Pal distinction). And you can use the prebuffer, which is also not possible in overcrank. So I use the normal 60p instead of the overcranck. With the EX3 that gives more flexibility. The biggest problem is that in all cases you have to change a lot of settings. NTSC/Pal in camera, framerate in camera, codec in nano, bitrate in nano. It would have been nice if in the EX line the distinction between Pal and NTSC would not be there (the framerates could all be in the same menu option) and the awaited Profile Settings in the nano will also be very welcome to make it all easier.

Ron Aerts · October 6th, 2010, 02:07 PM

Take care of the fact that art.light in europe is 50Hz when youre shooting 60. In some cases you'll loose a stop or 2. In daylight there are no problems...

Luben Izov · October 6th, 2010, 02:20 PM

Quote:

Originally Posted by Cees van Kempen

............The biggest problem is that in all cases you have to change a lot of settings. NTSC/Pal in camera, framerate in camera, codec in nano, bitrate in nano. It would have been nice if in the EX line the distinction between Pal and NTSC would not be there (the framerates could all be in the same menu option) and the awaited Profile Settings in the nano will also be very welcome to make it all easier.

Hi Cees,
You are right about it, but , hopefully as Dan have said before, CD is working on a new Firmware that would allow "Settings Profile" so when set it ones you would be able very quickly to go from mode to mode in a click of a button. I personally am really excited about it and looking forward to it. I only hope that CD would implement more then enough "Optional Profile Settings" so that we don't run out of options... ;-)
Cheers

September 28th, 2010, 08:36 AM	#16
Dan Keaton Inner Circle Join Date: Dec 2002 Location: Augusta Georgia Posts: 5,421	Dear Friends, We are trying to be honest and open when we report the reduced bit rate when cranking. But, there is more to this than is obvious on first glance. The reduced bit rate, is the actual target bit rate per second, and our message is accurate. The actual bit rate per frame remains the same as the full requested bit-rate. Thus, on a frame by frame basis, one gets the same bit-rate, but if there are one half the number of frames per second, then the "Bit-Rate per Second", is one half the normal requested bit-rate. We force "I-Frame Only" when cranking is active. When using our Over and Under-Cranking feature, if the Base Rate and the Crank Rate are the same, then the audio will be fine, both embedded and analog audio. This is a nice tool, for some cameras, to obtain certain frame rates that are otherwise unsupported by the camera. As always, I hope this helps. __________________ Dan Keaton Augusta Georgia

September 28th, 2010, 09:08 AM	#17
Cees van Kempen Major Player Join Date: Jan 2010 Location: Nieuw-Vossemeer, The Netherlands Posts: 455	Steve, as Dan describes Piotr is right. Since it will be I-Fo anyhow, quality wise it does not make any difference wheather I use overcrank or just shoot 60p. The latter however always gives sound and gives the opportunity to shoot 60p and in Cimema Tools bring it down to 25p. The 60 to 25 conversion is not able in overcrank in the nano (as in many devices there still is the NTSC vs Pal distinction). And you can use the prebuffer, which is also not possible in overcrank. So I use the normal 60p instead of the overcranck. With the EX3 that gives more flexibility. The biggest problem is that in all cases you have to change a lot of settings. NTSC/Pal in camera, framerate in camera, codec in nano, bitrate in nano. It would have been nice if in the EX line the distinction between Pal and NTSC would not be there (the framerates could all be in the same menu option) and the awaited Profile Settings in the nano will also be very welcome to make it all easier.

October 6th, 2010, 02:07 PM	#18
Ron Aerts Regular Crew Join Date: Feb 2010 Location: Drachten, Netherlands Posts: 179	Take care of the fact that art.light in europe is 50Hz when youre shooting 60. In some cases you'll loose a stop or 2. In daylight there are no problems...