[mythtv-users] Poor quality/performance on mytharchive compared to DVDstyler

John Pilkington J.Pilk at tesco.net
Thu Mar 22 23:52:44 UTC 2007


Paul Harrison wrote:
> Robin Gilks wrote:
>>> I reset those and will try this again (realizing that 720x480 will give me
>>> larger file sizes without appreciable improvement in visuals). But my
>>> original
>>> question still stands: what is DVDstyler doing with 480x480 MPEG2s quickly
>>> and
>>> cleanly that Mytharchive is doing ineptly?
>>>
>>> If DVDstyler is a frontend to the same set of command-line linux DVD
>>> mastering
>>> utilities that Mytharchive is using, why is DVDstyler capable of handling
>>> this
>>> task quickly and correctly and MythArchive is not?
>>>
>>> Hm?
>>>     
>> If you take a look at the mythburn.py script you will find a function that
>> will help you decide what resolution to record at to remain DVD compliant
>> when burning.
>>
>> This function is: isResolutionOkayForDVD
>>
>> Use your favourite editor to have a look at that and the magic numbers in
>> it (its only 4 lines, you can't miss it) will give you all the clues
>> you'll need.
>>
>> As for DVDstyler, I guess it produces non-compliant DVDs...
>>
>> And remember, its the bit rate that determines the filesize, not the
>> resolution. I recommend the info at:
>>    http://www.mediachance.com/dvdlab/tutorial/bitrate.html
>>
>> 
No doubt this is true, but I recorded (DVB-T, UK, ITV3) a 2 hour show 
(after transcoding to remove commercials) transmitted at a resolution of 
544*576, size 2.11GB.  Mytharchive by default converted this to 720*576 
with ac3, which almost filled a DVD, and took around 2 hours. (2.66Ghz 
P4).  Mytharchive without re-encoding retained about the original 
filesize and mp2 sound, and was much quicker.  I've apparently gained 
standards compatibility but the end result viewed in Myth or my 
standalone player looks much the same - and fully satisfactory in non-HD 
terms.

John P
> 
> The list of valid resolutions is also on the wiki page :-
> http://www.mythtv.org/wiki/index.php/MythArchive#FAQ
> 
> Paul H.
> 
>


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