[mythtv] Question/request: mythtranscode resampled output
Joseph A. Caputo
jcaputo1 at comcast.net
Sun Oct 19 02:06:01 EDT 2003
Chris Petersen wrote:
>> Anyway, I
>>suppose I could try piping the raw audio through sox to resample.
> If you tell me how to do this, I'm more than happy to hook it up to
> nuvexport. I just haven't had time (and not much incentive,
> unfortunately) to research it and figure out how to do it myself.
Yeah, I just tested running sox on the raw mythtranscode output... seems
to work OK. Haven't tested how it would work in the nuvexport pipeline,
but I think you know I'm interested in resampling for the SVCD
conversion... not sure tcmplex (or maybe it's toolame?) likes 32000 Hz.
I always get no sound in my MPEG-2 SVCD files made with nuvexport, and
it's been suggested that they need to be 44100 Hz (or was it 48000?).
Anyway, the command I used was 'sox -t raw -r 32000 -s -w -c 2
fifodir/audout -r 44100 out.wav'. We can't use format auto-detection
since there's no file header in the FIFO output from mythtranscode, so
this forces sox to assume raw (-t raw) Signed (-s) 16-bit (-w) 2-channel
stereo (-c 2) sound @ 32000 Hz (-r 32000) and convert it to WAV format
(autodetected by filename) @ 44100 Hz (-r 44100). Probably want to pull
the source sample rate from nuvinfo, and have the output sample rate be
a user option. Also, I'm not sure what output format would be best...
this will be piped to toolame, presumably, so maybe we just want to
output resample raw instead of converting to WAV. The sox man page is
pretty helpful. If I have some time maybe I'll try to rig it up myself,
but I haven't really bothered to learn Perl yet.
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