Red Hat Bugzilla – Bug 78300
Tempo/timing is 4-5x speed during playback with playmidi/xplaymidi compared to RH7.2
Last modified: 2014-03-16 22:32:26 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003
Description of problem:
playmidi playback through internal AWE32 or to external /dev/midi
does not set initial tempo correctly.
The effect is similar to what you would hear if you played a 33 1/3rd rpm record
at 78 rpm speed. The songs are played roughly 4-5x normal speed.
With RH7.2, playmidi -e -D /dev/midi midfile would play correctly.
When I upgraded to RH8.0, the playback is 4-5 times as fast, but not
consistently for the same midi file.
Effect reproduced with many different midi files using internal sound care
synthesizer as well as through external midi synthesizers.
Rendering with timidity maintains consistent tempo, but is not capable to
rendering to external hardware.
I vaguely remember some readme notes during the upgrade related to playmidi and
Linux kernel timing overall being changed with RH8.
A playmidi workaround exists by using the -t tempofactor option, but guessing
the tempo factor to apply is hit or miss for each MIDI file.
Consistent values for my dual PII-450 i686_smp machine seem to be between 4.5
and 5.0 for a given file.
I would like to understand:
How RH8 timing changes (HZ?) could be misinterpreted by playmidi?
What has changed with playmidi/xplaymidi from 7.2 to 8.0?
How to apply a single change/fix/update that will create correct playback tempos
again for a bulk of the MIDI files I use?
Could a single setting restore 7.2 configuration compatibility?
Version-Release number of selected component (if applicable):
RedHat Linux 8.0 Kernel 2.4.18-18.8.0smp for i686
Steps to Reproduce:
1. playmidi -e -D /dev/midi midifile.mid
Actual Results: Song playback occurs at something like 4-5x normal speed.
Expected Results: Song playback at correct tempo... which occurred on RH7.2
before upgrade to 8.0.
"Normal" speed: playmidi -t 4.5 -e -D /dev/midi midifile.mid
The 4.5 number is not consistent... this was found through trial and error and
tends to range from 4.0-5.0 to get "correct" sounding speed.
Consistent using either external midi OR internal AWE32.
Timidity always plays ok on internal sound card, no external playback available
playmidi is not included in 8.0. But yes, it is probably something to do with
the HZ changes.