Axio capture codecs and bitrates

[David Cherniack]

Mark,

Best to ask this in the Matrox forum. But I’ll do what I can here.

There is no intermediate mjpeg compression in Axio. The intermediate level of compression in sd and hd is mpeg2 iframe where you can set the bit rate 25-100 mbs in SD and 50-300 mbs in hd. This is 8 bit but a lot of the compression parameters are addressable.

I’ve looked at 100 mbs HD and it’s indistiguishable from uncompressed.

David
AllinOneFilms.com

[Mark Palmos]

[David Cherniack] “The intermediate level of compression in sd and hd is mpeg2 iframe where you can set the bit rate 25-100 mbs in SD and 50-300 mbs in hd”

hmmm mbs…
megabits?
er, so any idea what those bitrates are approx in kbf?
what’s the quality like compared to mjpeg?
I see you can playback digisuite files, but not capture mjpeg.
For me this is still a bit of a frustrating limitation of PP or at least the cards that support it.

How are you liking your Axio?
Till later,
Mark

[David Cherniack]

[mark palmos] “so any idea what those bitrates are approx in kbf”

Apples and oranges, Mark.

The mpeg2 iframe is great but you should see it for yourself. Try to get a demo.

The Axio is excellent. Best bang for the buck out there right now.

David
AllinOneFilms.com

[Jason J rodriguez]

Sony quotes their IMX I-frame MPEG-2 50Mb/s format as “digi-beta” quality. It’s not completely digital betacam quality of course (Digibeta is 10-bit for starters, and only 2:1 compression, where-as 50Mb/s is very close to 3:1 compression), but it’ supposedly very close image-quality-wise. So 100Mb/s I-frame MPEG-2 should look very nice (about 1.5:1 compression).

Jason Rodriguez
Virginia Beach, VA

[Dave Friend]

[mark palmos] “megabits?”

Mark,

If it helps at all remember that DV is 25mb/s which translates into about 13GB per hour of drive space – including stereo audio.

As far as translating to kb/f here’s my take on it. This is probably based on incorrect assumptions but it’s probably not too far off.

Start with 25,000,000 bits per second;
Assume 8 bits per byte for 3,125,000 bytes per second;
At the PAL frame rate of 25fps you get 125,000 bytes/frame or 125kB/f.

IMO, I-frame mpeg looks as good if not better than mjpeg. Using 25Mb/s for off-line work seems wholly adequate to me.

Dave

[Mark Palmos]

Hi guys,
yeah, thinking of DV quality and knowing that is 25 gives me an idea… thanks.

I am suprised DV is so low Dave, I thought (doing it another way) being 1:5, DV would be about 200kbf given one frame is about 1mb…

I was at a video expo today and there was massive interest around the Adobe booth, good to see.

Thanks for doing the maths Dave,
Till later,
Mark.

[Mark Palmos]

Hi guys,
yeah, thinking of DV quality and knowing that is 25 gives me an idea… thanks. I’m a bit disappointed it does not go lower than 25 though, I would prefer to offline at 10 then online at 50 or 100.

Thanks for doing the maths Dave, I am suprised DV is so low Dave, I thought (doing it another way) being 1:5, DV would be about 200kbf given one frame is about 1mb…

I was at a video expo today and there was massive interest around the Adobe booth, good to see.

Till later,
Mark.

[Alex Udell]

Hi Mark…

Long time…

Working for PEI again….and we’ve been very successful with Axio.

The MPEG Codec is visually great. Data Rates are low so they don’t tax drives at all….

Making the the comparison to KBF is an exercise in futility, because MPEG compression is entirely different than MJPEG…

Nice thing is that you can mix all the differnt codecs on the same timelilne….

Give it a test drive….you won’t be sorry….

Axio is rockin…

Probably the nicest thing (aside of the pure amount of real time performance) is that you can apply the fx like plug ins in the order you need them….not the order the hardware dictates…..

The approach to audio is a little funky in 1.5, but V2 seems like it’s rectifying that…

Cheers my friend…

Alex Udell