[mythtv-users] Mytharchive errors

Rod Smith mythtv at rodsbooks.com
Tue Dec 9 00:20:30 UTC 2008

On Monday 08 December 2008 05:48:29 pm Harry Devine wrote:
> OK, I understand that part, but I just can't seem to figure out why the
> command that Mytharchive is putting together is failing.

It's buggy. Although there may be a simple fix for your specific problem, it's 
unclear to me, given the symptoms you've presented, what that fix might be. 
It could be something simple (I've one suggestion below), but it could be a 
problem buried deep in the source code for ffmpeg (or conceivably some other 
tool). You simply haven't presented sufficiently diagnostic information. 
(That's not a criticism; these tools are extremely unfriendly to novice 

>  48000 -acodec ac3 -f dvd "/tmp/work/1/newfile2.mpg"

I hadn't noticed this before, but you're creating a temporary MPEG-2 file 
on /tmp. This directory might or might not be big enough to hold the 
temporary MPEG-2 file. If it's not, then the partition is filling up and the 
process will stall or crash. I believe there's a setting in the MythTV user 
interface for where MythArchive stores its temporary files. That directory 
should be on a partition or logical volume with lots of space -- MythArchive 
will be storing data equal to at least two DVDs in size there (maybe three or 
even four; I'd need to verify that). Alternatively, you can type the command 
by hand but change the location of this file to a directory where you know 
you've got lots of space and see if it finishes this time.

> Lastly, I'll try the midentify script.  However, when I tried your
> transcode script the other day, I wasn't really sure how to answer the
> questions.  Mainly due to my lack of understanding of the audio/video
> formats that are required.

Try these:

- bitrate: direct, ~3000000 bps (that's 6 zeroes); or by size, ~1500MB/hour
- 1-pass
- 4:3 or 16:9 aspect ratio, whichever it is (getting this wrong will just
  squash or stretch the copy)
- don't crop
- 720x480 final image size
- default audio track
- convert to 2-channel AC3 audio
- audio delay: 0

This should produce something that will be suitable for burning to DVD without 
an additional transcode operation. If you get something wrong (like in the 
aspect ratio or cropping), it'll still burn to DVD, but it'll be improperly 
cropped or be stretched or squashed.

Note that if my (very tentative) hypothesis about your running out of disk 
space on /tmp is correct, transcoding in this way isn't likely to help; when 
you run MythArchive on the transcoded recording, it'll still need a lot of 
disk space to prepare the image, and it'll run out if you're using a 
too-small /tmp.

Rod Smith

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