[mythtv-users] IVTV Bitrate & Resolution
Michael T. Dean
mtdean at thirdcontact.com
Sun Mar 25 17:10:00 UTC 2007
On 03/25/2007 09:50 AM, Cory Papenfuss wrote:
>> b) 720x480 is the maximum DVD-compliant resolution for NTSC format.
>> 720x576 is the maximum DVD-compliant resolution for PAL format. If
>> you're recording NTSC, you should /not/ use >480 pixels for the "Y"
> ... or <480 for that matter. NTSC has 480 visible lines with
> interlacing. Using anything other than ___x480 is generally a bad idea.
> Even 352x480 produces pretty good (VHS-quality) recordings. 352x240 looks
> like crap. In fact, I recall playing around with that at one point.
> IIRC, recording at 176x480 looked better than 352x240 (same number of
Agreed, but was trying to emphasize the >480 doesn't help since the OP
is using an unusual >NTSC, but <PAL resolutino. (However, since the OP
is using PAL, he should use 576.)
>> d) Due to the electronics in use on the PVR-x50's, you will be unable to
>> improve quality of NTSC recordings by using any resolution > 640x480.
>> You will likely be unable to improve quality of NTSC recordings by using
>> any resolution > 480x480. However, due to the scaling issues with the
>> PVR-150 and PVR-500 and due to the fact that neither 640x480 nor 480x480
>> is DVD-compliant resolution, many people record at the (too-high for the
>> electronics) resolution of 720x480.
> 704x480 is also a DVD-friendly resolution. Not much difference,
> but no point in doing 720x480 either.... it's not "more standard"
However, AIUI, 704x(480|576) is a "cut" resolution--which is supposed to
have clean edges. DVD's with video at 704x(480|576) are supposed to be
played back with less overscan (though I don't know of any specific
players that actually do so).
Since the PVR-x50's do /not/ have clean edges on their recordings, my
recommendation is to stay away from 704x(480|576) unless transcoding
/and/ cropping. Otherwise, you may stumble across some player that does
overscan less and you'll see black frame and/or jaggies and/or rainbow
edges on the TV.
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