[mythtv] fixes to mythburn.py

T.Brackertz at gmx.net T.Brackertz at gmx.net
Tue Sep 27 14:08:02 UTC 2011


Hi,

as I had trouble with bugs in mytharchive I fixed a couple of bugs.

Now I want to contribute the fixes but I'm not sure if I should open several tickets or only one ticket.

(It's the first time I get involved in the development of mythtv and I couldn't find an answer in the FAQs and I found many tickets with patches solving many bugs at once.)

Below there is a description of the changes.

So what's the next step to do?

Thanks, Stefan


-----------------------------------------------------------
Patches in mythburn.py
----------------------
----------------------

typos
-----
all irrelevant



Medium handling:
----------------
former issues:
- no possibility to cancel process
- one has to be fast enough feeding the device, otherwise the process cancels
- some devices need more time to close the tray. They get hard-resetted all the time. No chance to burn a disk, if it is not put in before the script is started
- if you use a disk of wrong type you don't get a chance to put in a correct one. The whole process cancels

changes in BurnDVDISO()


Integration of project-x
------------------------
until now:
After the run of project-x its logfile is parsed (in renameProjectXFiles()) to find out the filenames of the files produced by project-x and to associate them to the streams

issues:
- not very reliable: in many constellations (e.g. recoded .flv-videos) the logfile doesn't fit the expectations. Although there is a fallback mechanism in many cases the script crashes while parsing before reaching the fallback
- the format of the logfile seems to change often if there is a new version of project-x. The parser has to be renewd all the time. (the recent one works for project-x 0.91 but not for older ones)

solution:
- An 0.91 project-x learned a new command line option (-set ExternPanel.appendPidToFileName=1) which causes project-x to use filenames for the output containing the PIDs and SubPIDs in a predictable manner. This should work with upcoming versions, too.
- Therefore no more parsing is necessary.
- Nevertheless there is still a fallback mechanism as in some cases (e.g. recoded mggs) mytharchivehelper gives strange IDs which makes it impossible to find the wanted files by ID
- As the current parser relies on project-x 0.91 as well there is no regression by the fact that at least version 0.91 is necessary now. (The version dependency at the beginning of the sript claiming for project-x 0.90.4 was outdated anyway.)

changes in runProjectX(), renameProjectXFiles() is obsolete now


Divide-by-zero-error when requantising
--------------------------------------
see:
http://code.mythtv.org/trac/ticket/8598#comment:2

issue:
If M2VRequantiser fails for some reason (probably it is not installed) the script crashes with a missleading error message.

reason:
The exit-code of M2VRequantiser is evaluated too late: After then run the size of the produced file is evaluated which gives a divide-by-zero-error. The exit-code of M2VRequantiser is evaluated thereafter, which means never because the script crashes before.

solution:
change the order

changes in runM2VRequantiser


Misleading log-entry
--------------------
issue:
The log-entry produced by getStreamInformation() sometimes mentions the wrong file as the filename is hard-coded

solution:
use the appropriate variable

changes in getStreamInformation()


Inconsistent string-handling in the whole script
------------------------------------------------
issue:
many errors and crashs when sript is used with recordings having special characters in their title or videos with special chars in the filename.

reason:
One part of the strings is unicode (mainly coming from parsing the xml-files), another part is utf-8-encoded (mainly coming from database). They get mixed up and / or get printed to logfile or console unencoded or double-encoded. This results in many errors.

solution:
Consequently use unicode-strings:
- make the database-object use unicode-strings in getDatabaseConnection()
- encode strings to utf-8 before printing to logfile or console in write() and runCommand()
- remove all encode- and decode-statements in the rest of the script


Endless growing work-directory
------------------------------
issue:
In some rare cases in which many DVDs with many small and one big title are created the work-directory theoreticallly grows endless

reason:
Before a new file is written to disk the old file with the same name is deleted but the rest is not.
Imagine the following situation:
Create a DL-disc with 20 titles, all very small, only the last one having 8GB. You get 20 subdirs in the work-directory of which the "20"-directory is very big. All together they have 9GB.
Next step: The same as before but with only 19 titles. Result: Only the first 19 dirs of the last run get deleted, the big "20"-dir stays. But there is a new big "19"-dir. All together they have ~17GB
An so on. You end up with a work directory containing at least 160GB

solution:
delete everything in the "work"-dir at the beginning instead of incrementally deletion. Also shortens the code.

new deleteEverythingInFolder()-function and changes at some other places
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