FireFly Media Server › Firefly Media Server Forums › Firefly Media Server › General Discussion › can firefly resample to 48khz?
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07/06/2008 at 8:54 PM #2490AnonymousInactive
If you use firefly to transcode a flac etc can it also resample from 44.1khz to 48khz as this would remove the noise issue with the roku m1001?
08/06/2008 at 12:28 AM #17170stretchParticipantI’m not sure if it can but i did a bit of digging.
In mt-daapd-ssc.sh is a line that reads
$FFMPEG -vn -i "$FILE" -f wav - | $WAVSTREAMER -o $OFFSET $FORGELEN
ffmpeg documentation says that -vn is Disable Video, -i is Input filename, -f wav forces wav output.
The documentation also lists an -ar freq switch that sets the audio sampling frequency
http://ffmpeg.mplayerhq.hu/ffmpeg-doc.html#SEC11
http://wiki.fireflymediaserver.org/Transcoding_HOWTOI haven’t tried this & have no idea if it will work as i have M2000’s that don’t upsample to 48kHz
I haven’t paid much attention to the M1001 noise problem but as i understand it, it’s an alias frequency problem from the 44.1 -> 48kHz conversion process.
You might get better results permanently converting the files to 48kHz using something like dBPower Amp and storing them in a separate library for use with the SB08/06/2008 at 8:52 AM #17171fizzeParticipantYou would have to run firefly on a reasonable PC (not on a slug, for instance). I’m sure it can be done but I doubt the results would be much better than the resampling on the SoundBridge.
-ar 48000
would tell ffmpeg to resample the audio output, give it a show ๐
08/06/2008 at 9:06 AM #17172AnonymousInactiveThanks for the quick replies guys will give it a go, though as I use a ls pro I will have to see how well it transcodes. I will also rip a couple of albums in 48khz using db power amp (stretch, thanks for letting me know about this app) to compare to see how well it works.
08/06/2008 at 6:24 PM #17173AnonymousInactivehit a snag: my firefly on the lspro has the 1596 build and I can’t find anywhere with the 1696 for arm9 (not the debian one) and that says it works. This means I don’t have mplayer. I can still transcode as firefly can read m4a and I have the alac decoder installed but I don’t know what option (i.e. -ar for mplayer) to resample using just the decoder.
Hope that made sense. appreciate any ideas you guys have on if the decoder can resample and what the option command might be?
08/06/2008 at 6:48 PM #17174AnonymousInactivewell I have a couple of options on the mt-daapd-ssc.sh
first:
alac_file() {
$ALAC --resample {48000} "$FILE" | $WAVSTREAMER -o $OFFSET $FORGELENand
alac_file() {
$ALAC "$FILE" | $WAVSTREAMER -o $OFFSET $FORGELEN -ar 48000let me know if I have gone wrong.
08/06/2008 at 6:54 PM #17175AnonymousInactivethe new version
FILE=*.m4a
$FFMPEG -vn -i "$FILE" -f wav - | $WAVSTREAMER -o $OFFSET $FORGELEN -ar 48000The issues with using mplayer is I am not sure it will work on a lspro as it is only 400mhz arm processor
09/06/2008 at 1:58 AM #17176stretchParticipanti may be wrong but i think it should be
$FFMPEG -vn -i "$FILE" -f wav -ar 48000 - | $WAVSTREAMER -o $OFFSET $FORGELEN
09/06/2008 at 2:17 PM #17177fizzeParticipant@threeminutes wrote:
hit a snag: my firefly on the lspro has the 1596 build and I can’t find anywhere with the 1696 for arm9 (not the debian one) and that says it works. This means I don’t have mplayer. I can still transcode as firefly can read m4a and I have the alac decoder installed but I don’t know what option (i.e. -ar for mplayer) to resample using just the decoder.
Hope that made sense. appreciate any ideas you guys have on if the decoder can resample and what the option command might be?
The Linkstation runs on an ARM chipset, and thus lacks floating point capabilities in hardware. They can be emulated in software, but the performance is lacking, to say the least.
Resampling is a very floating-point intensive procedure, and I severly doubt that the LS is up for that. ๐ ๐
11/06/2008 at 10:55 AM #17178AnonymousInactiveThanks for the replies fizze and stretch, looks like I am better just resampling the content I have instead of doing it on the fly. It was worth a thought, just might have to invest in a SB3 though slimserver is meant to run quite slow on the LS pros so.
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