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can firefly resample to 48khz?

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  • #2490
    Anonymous
    Inactive

    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?

    #17170
    stretch
    Participant

    I’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_HOWTO

    I 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 SB

    #17171
    fizze
    Participant

    You 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 😉

    #17172
    Anonymous
    Inactive

    Thanks 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.

    #17173
    Anonymous
    Inactive

    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?

    #17174
    Anonymous
    Inactive

    well I have a couple of options on the mt-daapd-ssc.sh

    first:

    alac_file() {
    $ALAC --resample {48000} "$FILE" | $WAVSTREAMER -o $OFFSET $FORGELEN

    and

    alac_file() {
    $ALAC "$FILE" | $WAVSTREAMER -o $OFFSET $FORGELEN -ar 48000

    let me know if I have gone wrong.

    #17175
    Anonymous
    Inactive

    the new version

    FILE=*.m4a

    $FFMPEG -vn -i "$FILE" -f wav - | $WAVSTREAMER -o $OFFSET $FORGELEN -ar 48000

    The issues with using mplayer is I am not sure it will work on a lspro as it is only 400mhz arm processor

    #17176
    stretch
    Participant

    i may be wrong but i think it should be

    $FFMPEG -vn -i "$FILE" -f wav -ar 48000 - | $WAVSTREAMER -o $OFFSET $FORGELEN 
    #17177
    fizze
    Participant

    @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. 🙁 🙄

    #17178
    Anonymous
    Inactive

    Thanks 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.

    #17179
    Anonymous
    Inactive

    >Thanks for the replies fizze and stretch, looks like I am better just
    > resampling the content I have instead of doing it on the fly.

    Before doing anything, have you already verified that there is a noise issue. It’s a complete non-issue in my system.

    #17180
    fizze
    Participant

    Haha! Good one!
    Please do not get us started on the issues of the SoundBridges here 😉

    This has been discussed to death in RoKu’s forums a thousand times. If you’re bored you might want to do a search for “noise” there 😀 😆

    Anyway, if you really cannot live with the noise, than may I suggest you get a used M1000, or M2000 since they do not resample to 48kHz.

    #17181
    Anonymous
    Inactive

    As a headphone user (HD650) with headphone amp it is quite noticable (I often listen to classical music) and it will probably be even worse when I get my new DAC. To be honest I can live with it for now as you can only hear it when the music has quiet sections but will look into alternatives if it becomes more pronounced with the DAC. Appreciate all the help you guys have given.

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