Settop DVD recorder tricks

[dphirschler]

I am sure certain DVD recorders do certain things to try to squeeze more video on the discs. What are some of the tricks? For instance do some recorders convert to 24fps and encode as progressive? I am sure all recorders fiddle with bitrates, but what about capture resolution? Do any of the recorders give you the option of recording at say 352x480? Do they compress the audio to AC3 by default? Do any of the recorders somehow do VBR encoding? Do any attempt IVTC?

Finally, what kind of control do these recorders give the user over these settings: capture resolution, video framerate, bitrates, audio bitrate, audio AC3 or PCM, audio stereo/mono.


Darryl

[Capmaster]

I am sure certain DVD recorders do certain things to try to squeeze more video on the discs. What are some of the tricks? For instance do some recorders convert to 24fps and encode as progressive? I am sure all recorders fiddle with bitrates, but what about capture resolution? Do any of the recorders give you the option of recording at say 352x480? Do they compress the audio to AC3 by default? Do any of the recorders somehow do VBR encoding? Do any attempt IVTC?

Finally, what kind of control do these recorders give the user over these settings: capture resolution, video framerate, bitrates, audio bitrate, audio AC3 or PCM, audio stereo/mono.


Darryl

Darryl,
They do a few things to try to squeeze a lot onto a disc. The Panasonic DMR-E50 I have not only has VBR, but it has "FR" - flexible recording, which ...depending on what you want and how you set it up ....either adjusts the bitrate on the fly to use all the remaining space on the disc for that recording, or it makes sure the current recording doesn't take too much space if you're planning another recording on the disc before finalizing.

It also has "Hybrid VBR", which it defaults to in the options unless you turn it off. This not only changes the bitrate dynamically, but also changes the resolution as needed to squeeze in as much block-free video as it can.

It works great if you're not going to edit it on the PC later. If you are recording to DVD-RAM or -R and plan to open it on a PC to edit, add better menus, etc., it usually blows the editing app's mind having a video with multiple resolutions present.

The overall result is quite good. Even the longer recordings show remarkably little in the way of undesirable artifacts like macro blocks, motion traces, hesitation, etc.