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RGMdddd
09-05-2004, 03:18 AM
Richard -

Based on some of your comments in other threads, I am curious about the use of certain codecs depending on intended use.
Most of the work I do involves imagery that I have created myself for the particular production that I am working on. In addition, these tend to be cued shows that will run sequentially via the [GO] button. Therefore, all of the content can be created so it will always be played forwards and from frame 1 to its endpoint or layer fade out - whichever comes first.
I recognize that this is not your intended market or design for Catalyst but the product works quite well in this market segment as well.
That all having been said and providing that those provisions will always be in place, do you feel that certain codecs are better than the current crop we are advised to use?
Thanks in advance for any information you may have.

samsc
09-05-2004, 08:05 AM
Richard -

Based on some of your comments in other threads, I am curious about the use of certain codecs depending on intended use.
Most of the work I do involves imagery that I have created myself for the particular production that I am working on. In addition, these tend to be cued shows that will run sequentially via the [GO] button. Therefore, all of the content can be created so it will always be played forwards and from frame 1 to its endpoint or layer fade out - whichever comes first.
I recognize that this is not your intended market or design for Catalyst but the product works quite well in this market segment as well.
That all having been said and providing that those provisions will always be in place, do you feel that certain codecs are better than the current crop we are advised to use?
Thanks in advance for any information you may have.

The codecs that are using interframe compression - h263- mpeg2 - are the ones trying to get the most out of limited bandwidth - because they are used in dvd's or in streaming or broadcast systems where transmission bandwidth is the premium.

For a DVD you have to get the bitrate below 9Mbits/sec including audio.
And for internet streaming below 1Mbit/s

The bit rate of a single uncompressed YUV 8bit ntsc stream using 4:2:2 coding is 720x480x16x30 = 186Million bits/second ( e&oe...) about 20MBytes/sec

So to get this onto a DVD using MPEG2 you have to use something of the order of 20:1 compression - and still get a good picture - the only way to do this is to use interframe compression - look at the differences between consequetive frames and figure out a way to remove redundant information.

DV-Ntsc is only 5:1 compression. Much less than MPEG2. around 25MillionBits/second
DVPro 50 is 50MillionsBits/second

We do not need to use interframe compression because our restrictions are not based on the bandwidth of the data transport system.

Our data transport system can manage 500MBit/s at least.

All of the current codecs DV- photojpeg and mjpeg - uncompressed will be the ones to use way into the future.
They are the easiest to edit, the easiest to decode. The are almost foolproof.
We do not have any need for interframe compression.

What will happen in the future is that people will start to use DVCPro50 if they need 'more quality' or photojpeg at lower compression rate.

People will also start to use footage at 720p or 1080p on more layers. But they will use photojpeg or DV-NTSC or DVCPro HD.

samsc
09-05-2004, 08:12 AM
The current codecs that you are advised to use are based on end to end system testing my me. Disc to screen performance.

There is a compromise between playback performance and image quality that has been in digital video throughout its entire history.

This can be summed up as follows:

DV-NTSC is the fastest and only codec that will give you 30fps on 4 layers at 720x480 with a single or dual scsi 10k/15k system or raptor.

DV-NTSC/PAL is a good codec. It is used in all current professional and amateur DV cameras - and is also used in professional DV-CAM.

If you dont need 4 layers at 30fps - then you can use whatever will give you what you need:
Photojpeg, mjpeg, DVCPro 50, uncompressed.
These will give you between 2 and 3 layers of playback at 30fps.