Originally Posted by qz3fwd
A DVHS deck can record anything off your cable company DVR so long as the content is flagged either copy freely or copy once.
... since the DVHS deck is 5C-compliant, established during the firewire handshake between the DVR and VCR, the DVR will send the data.
The DV-CAM deck is not 5C-compliant, so the DVR will not send anything to it over firewire.
Them's the rules of 5C.
You will not be able to capture copy one material on a computer, because the stream is encrypted by the DVR and no decryption keys are available to decrypt nor authenticate a connection between the devices.
I believe I had a very informative discussion on the subject of encryption/decryption with a super-knowledgeable forum member, GSR, back in November 2010. This discussion (which got technical) pertained to the Ceton 4-tuner cablecard enabled product, as well as many related subjects such as protected vs. unprotected WTV recordings from Windows Media Center, DRM, encryption/decryption and where it occurs and the keys involved, transfers over firewire to PC vs. 5C-compliant DVHS VCRs, etc.
The Ceton thread is very long, but the particular subject of 5C-protection vs. the separate subject of encryption/decryption and exactly WHERE it occurs, starts at about this point in that thread and runs for a few pages
Essentially, the notion of 5C copy protection is completely independent of encryption/decryption. And it's possible to have either one or both involved with a particular program.
GSR's explanation is that during playback by the tuner in the DVR, the cablecard in the DVR decrypts the original program encrypted data which was written to the hard drive when recorded, if necessary. The same happens "live", if no recording is involved. The same thing happens in Win7 WMC, reading encrypted WTV recordings. The cablecard present in the Ceton card does the decryption required during original arrival of encrypted programs either for "live" TV watching or for recording. If necessary, Win7 re-encrypts the program with a new DRM key for recording to "copy protected" WTV format. For Win7 WMC recordings to WTV, the original program content gets decrypted by the cablecard, and then re-encrypted by Win7 using a sophisticated key unique to that PC and Win7 and point-in-time.
And, according to him, the data stream sent out over firewire from DVR to 5C-compliant JVC DVHS VCR is similarly decrypted (if it needed to be) but retains its 5C copy-protection flags.
When it arrives at the JVC DVHS VCR, it is re-encrypted for recording to tape (if it needed to be), using a new encryption key unique to JVC (or maybe to the entire product world of DVHS VCR's). So while this recording can be played back (by decrypting, using this key) by other JVC DVHS machines (and perhaps Mitsubishi DVHS machines as well, if the key one available to all 5C-compliant DVHS VCR products when they were still being manufactured), it cannot be played back by my Panasonic PV-HD1000 DVHS VCR because it is NOT 5C-compliant and is incapable of decrypting.
The discussion continued on to WMC, DRM for WTV, whether the programs come to you encrypted or not from the cable company, if they're flagged copy once, etc. If marked copy-once, Win7 Media Center will encrypt them with a key that's tied to that PC so they can only be played on that PC. So the WTV file will have the 5C flag set to copy once and the file will also be encrypted using a unique very sophisticated time-based encryption key tied to that PC, and to that particular installed version of Win7.
Again... it was a very interesting and VERY informative discussion. I had always thought the data transmitted over firewire was still the original encryption, and that the decryption key was sent from DVR to VCR. GSR stated this was not true, and that the data sent out over firewire was first decrypted by the DVR using its own encrypt/decrypt key, and then re-encrypted by the VCR using a new encrypt/decrypt key. This governs what VCRs can actually play back the recording.
The 5C copy-once flag was sent as well, and recorded as well by the VCR, and controls whether or not the recording can further be copied from VCR#1 to VCR#2 or some other recording device.
Anyway, the important thing is that because the JVC DVHS VCR's are 5C-compliant, the DVR will send it program data over firewire for recording to DVHS tape, no matter whether copy-once or copy-freely. And all of these programs can be played back by the VCR to HDTV from this DVHS tape recording.