# help with comcast dvr 3416



## lstept (Dec 17, 2010)

i have a comcast motorola dch3416 dual tuner dvr. unfortunatley it only has 160 gb of hard drive. i have spoken to a comcast repair guy and he states that the fire wire port in the back is active. is there any way to attach an external hard drive to the port so that i can increase storage capacity. other cable companies have gotten around the drm issue by making sure that when the drive is connected, its contents are completely erased and the drive is formated only to work with that box. thanks for any help you have. lstept


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## etaf (Oct 2, 2003)

User Manual is here 
http://www.motorola.com/web/Busines...tic Files/DCH3416_User_Guide_537529-001-c.pdf

reading the manual it looks like the firewire port is just for outputting the video signal - like a HDMI connection and not really for a harddrive to copy material to.

I know on some of the humax machines you can copy material via the USB connection - but it does say that in the manual for the humax

But I may be wrong

it maybe possible to put a bigger harddrive into the box 
OR you may be able to play the recordings onto a DVD writer - but that takes time as you have to play the recording in real time 
What country are you in
- Standard Definition programs should not be DRM as there is some discussion about these being in public domain but i know the BBC are involved in some of these issues - and only allows HD programs to be played back on the same machine as recorded - but SD broadcast can be played back anywhere 
This was from some recent discussions on AV forums


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## lstept (Dec 17, 2010)

don't want to copy material, just want to increase hard drive space, can;t hack the box to put a larger drive in. i am in pittsburgh pa. usa. just need the box to recognize the external drive and format it for storage


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## gyrgrls (Nov 22, 2004)

lstept said:


> other cable companies have gotten around the drm issue by making sure that when the drive is connected, its contents are completely erased and the drive is formated only to work with that box. thanks for any help you have. lstept


Um, software like Passport and SARA, for DVR's in general, use dual filesystems, both proprietary.

The Video objects themselves are [usually] stored on an AVFS filesystem (partition), 
while the metadata, such as indexes, time to save, etc... are stored on a smaller partition, usually ITFS, Reiser or ext2, or a variant thereof. Due to fragmentation, the AVF and AVS files are nearly impossible to read without the metadata, since AVFS
is written to raw blocks, and indexed separately. Furthermore, the data may or may not be encrypted...
FORGET IT! 

Now, the AVFS parrtition contains the AVR and AVF files. This partition could be imaged by a program like Acronis , or the dd command in Linux, etc... after removing the drive from the DVR box, then swapping it back in, erasing it, to free up more space, but this is tedious, and there are no guarantees it will work right when swapped back in, without imaging the ENTIRE disc (and even then, if it's encrypted and/ or copy protected, you're still SOL).

I have always opted to record the programs I wanted to save at 1x, via a vidcap card (using PVR software), then just erase them from the DVR. That way, I don't have to go into the machine, and I have regular uncompressed MPEG 2 files on my computer hard drive. Yes, they were compressed on the DVR, so why re-compress them when copying to PVR?

YMMV

Anyway, save what you need before poking around inside the DVR, just in case it does get erased/formatted in the process.


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## gyrgrls (Nov 22, 2004)

More on AVR/AVF files: http://web.aanet.com.au/cameron/PVR-info/AVF-format.html


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## lstept (Dec 17, 2010)

thank you for that information, again i would rather not hack into the box.


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## antimoth (Aug 8, 2009)

Images from efate's link to the Motorola PDF Shows the external hard drive interface.

Some DVR's hook up easily to a external hard drive. Other do not. The box firmware either allows it or it doesn't. Sometimes it depends on the interface in the hard drive enclosure. What people do is buy a hard drive, an enclosure that supports E-sata, and an E-sata cable. Then they connect them, cross their fingers and the box either recognizes the drive or does nothing. Some companies sell the whole thing: drive, box, and cable, and they call it a cable expander.

Unless you know that external drives will work with your particular cable provider service and DVR box, it's a gamble. These guys might have experience. http://www.avsforum.com/avs-vb/forumdisplay.php?f=100

I've spoken with two cable installers from my service when they were around doing stuff, and neither of them knew that their equipment supported external hard drives until they saw mine sitting there.


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