[mythtv-users] MythArchive won't write to my DL DVD

John Pilkington J.Pilk at tesco.net
Tue Jan 16 09:55:31 UTC 2007

Kevin J. Cummings wrote:
> John Pilkington wrote:
>> Kevin J. Cummings wrote:
>>>> :-( /dev/dvd: 4173824 blocks are free, 4391419 to be written!
>>>> :-( write failed: No space left on device
>>> Obviously mytharchive is trying to write too much information to my DVD.
>>>  Shouldn't this have been caught during the "Create DVD" setup screens
>>> when I selected my videos?
>> This looks like the problem I had with the DVD iso image being too big.
>> I posted around 22 Dec on the user and (later) the dev list.
>>>> I think the problem arises because mythburn aims to create an image that 
>>>>> fills the physical storage capacity of the dvd, making no allowance for 
>>>>> formatting overheads.  The Mytharchive menu quotes available capacity as 
>>>>> 4.38 Gb, disk capacity as 4482 Mb; in the version that I have (FC5 
>>>>> atrpms) mythburn uses the latter.  It's an easy edit - does anyone have 
>>>>> a definitive value?
>>> After several trials I got an image that K3b wrote successfully when the 
>>> initial value of dvdrsize in mythburn.py was changed from 4482 to 4330.
>>> K3b reported the size of the written image as 4487 Mb, still apparently 
>>> 5Mb above threshhold.
>>> Mythburn uses a guesstimate (?) of 1.05 for the factor by which 
>>> multiplexing will increase the size of the video component, so YMMV.
> Interesting.  I've not (yet) had a problem with single layer DVDs.
> 4,700,000,000 / 1024 / 1024 = 4482.27 MB but
> 8,500,000,000 / 1024 / 1024 = 8106.23 MB
>> I'm now using a dvdrsize of 4300 in > 
>> /usr/share/mythtv/mytharchive/scripts/mythburn.py  (ATrpms fc5)
>> and get writable images.
>>> #Single and dual layer recordable DVD free space in MBytes
>>> #dvdrsize=(4482,8964)
>>> dvdrsize=(4300,8600)
> Which differs from the values being used above for DL DVDs.
> Where do these values come from?  Should a DL DVD be twice the size of a
> SL DVD?  And if so, then why are the disks labeled as 8.5GB and not
> 9.4GB????
> (Inquiring minds want to know!)
> In any event, after cutting out the commercials, the 4 episodes fit fine
> with no re-encoding on my DL DVD.  And both DVD players in the house are
> playing the MPEG-2 vidoes just fine.
> I'm going to try again tomorrow after tonight's next 4 episodes.  B^)
> Thanks!
The value of 4320 for a single-layer DVD was the first that I tried (in 
a decreasing sequence) that gave an image recordable by K3b with one 
particular set of recordings (and Myth version).  The reported image 
size still looked marginal, so I reduced it a bit more; perhaps it's a 
bit pessimistic but I haven't had an oversized image with it and the 
DVDs play well in Xine and my stand-alone player.

The internal MythTv player hangs when a DVD track is selected; so does 
the 'Play Created DVD' in the Mytharchive menu. (ATrpms bleeding 
0.21-149_trunk_r12353.fc5.at at i386)

I have no experience of double layer DVDs.  The value in the distro is 
twice that for a single layer, so I just doubled my SL value.

John P

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