what is the use of a IEEE-1394A Ports?

[vasulic]

Can anyone explain me the uses of IEEE-1394A Port?

[AlienTech]

They are kind of like USB ports developed by Apple called firewire. All digital cameras have IEEE interfaces so you can transfer and edit as well as control the camera from your PC using this port. You can do frame editing as well as copying video to your PC without loss unlike a video capture device where you have to convert a video signal to digital and then store it. I think its great...

You can also use special programs to backup your system onto your camera Right now the tapes cost a lot more than DVD's but store almost the same amount of data. But 3-4 years ago DVD's were much more expensive so they came in handy.

There are also hard drives which use this interface and it is faster than USB2. So to get 16X DVD writes you need to use IEEE instead of USB2 which maxes out around 12X.

But for me able to transfer video from my DV cam without dropping frames or loss of quality is the main benefit.
http://videosystems.com/mag/video_firewire_transfer/

[vasulic]

Thanks alien

[siriusb]

So to get 16X DVD writes you need to use IEEE instead of USB2 which maxes out around 12X.

Someone told me the same thing, but I've got a doubt.
See:
16x DVD is equal to 177.28 Mbps
and
USB 2.0 (Hi-speed usb) is 480Mbps

Now how do they (& you) say that usb2.0 don't have enuf bandwidth??

[AlienTech]

[quote="siriusb"]

USB 2.0 (Hi-speed usb) is 480Mbps

Now how do they (& you) say that usb2.0 don't have enuf bandwidth??

Just because something says its fast does not mean it is. if that was the case the American made cars with giant V8 engines would be the worlds fastest. Instead some small cars with much smaller engines like Porche are much faster. I had noticed that IEEE is much more consistent in speed and maintains it throughput while USB will peak and drop off. Also there are a lot of bad USB2 implementations. Like my MSI RS480 has a really bad USB chip set so its 50% slower than my el cheapo Intel Via speeds.
IEEE implementations are much more robust because the main chip set makers Lucent and TI did a good job initially. USB2 is now done mostly by Chinese. I have got 26MB/sec with both my USB2 and IEEE so that should be more than fast enough for 16X. But since USB2 can be interrupted, the 2MB buffer in the drive might not be able to hold enough data to compensate for any interruptions.
But even drive makers who have external chassis usually max out at 8X or 12X... None of them guarantee you can write @ 16X. Also consider the cost, LG 4163B costs like $50 and the external version with USB they sell for $70. While others with IEEE external versions costs double. $20 for an external case, interface, cables, power supply aint much.. You can imagine how much research and developmenet they put into it.

[AlienTech]

USB 2.0 vs. FireWire

Direct connection

http://www.ixbt.com/storage/usb-to-fw/w2k-direct.png

Via USB 2.0

http://www.ixbt.com/storage/usb-to-fw/w2kusb2.png

Via FireWire

http://www.ixbt.com/storage/usb-to-fw/w2k-fw.png

Connection Type: Direct --- USB 2.0 --- FireWire
Transfer Begin: 41900 Bytes/Sec --- 14200 Bytes/Sec --- 36100 Bytes/Sec
Transfer End: 25600 Bytes/Sec --- 14200 Bytes/Sec --- 25500 Bytes/Sec

http://www.digit-life.com/articles/usb20vsfirewire/

You can see that the IEEE transfer rate hits its max 40MB/sec while the USB2 implementaion is rather slow.
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[siriusb]

Er..um..nice. So, u mean to say that usb2 implementations don't follow the usb2 specification? If that's not what u mean, then I still don't get why usb2 with 480Mbps shud be slower than 1394a supporting only 400Mbps.

[Keith Sebastian]

Originally Posted by siriusb

16x DVD is equal to 177.28 Mbps
and
USB 2.0 (Hi-speed usb) is 480Mbps

Now how do they (& you) say that usb2.0 don't have enuf bandwidth??

USB 2.0 does not achieve 480Mbps in real world operating conditions. Quote from an article at tomshardware.com
USB 2.0 was developed to provide more flexibility for USB, especially for applications such as mass storage. All PC systems available today support USB 2.0, which increases bandwidth from 12 Mbit/s all the way to 480 MBit/s, or 60 MB/s. Real-world throughput is usually only just under 30 MB/s, but this is still more than enough for most newer external devices.

http://www.tomshardware.com/storage/...al-hds-01.html

Keith

[AlienTech]

Originally Posted by siriusb

Er..um..nice. So, u mean to say that usb2 implementations don't follow the usb2 specification? If that's not what u mean, then I still don't get why usb2 with 480Mbps shud be slower than 1394a supporting only 400Mbps.

Because of implementation. IEEE is designed to bus master without interruptions for continuous data transfers. But it still dont explain why it is much faster. So I would think it has to do with cheap and bad chip sets. I have USB2 external cases where 2 of them wont work faster than 15MB/sec while another 2 using a different chip set does 25MB/sec on the same hard disk. Anyone making such bad stuff for IEEE will immediately get returns because when they go home and hook up their DV type stuff to it you dont want your expensive video camera to sit there doing frame by frame video transfers and then rewinding to a frame it missed... Thats what amazed me about IEEE, I can transfer and capture in real time the video and it takes 60 minutes for an hour's video from the tape. It has never skipped... Even on a 500MHZ P3. Of course you cant do anything else and the computer appears to lock up. But it works.

[anispace]

Can some1 tell me how to capture pure video+audio from my DV cam(SONY DCR HC-40). The software provided with it captures video with some mp3 music mixed with it(which i do not want).

Also it takes upto 2hrs. in usb2.0. My DV cam supports Firewire but the cable isnt provided.So where can i get the cable.