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24bit PCM compress
yg2003618
post Nov 25 2010, 10:22
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anyone knows about how to compress 24bit PCM 48Khz audio, I know that most codecs process 16bit pcm. i want compress 24bit PCM at real time, 3:1 or 4:1 compress rate. who can help me? i know that subband adpcm maybe a choice. anyone knows more about that?

thanks alot.
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yg2003618
post Nov 26 2010, 03:09
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thanks everyone, my project is using an ARM7 cpu to compress and decompress HiFi audio/music(24bit 48K sample rate that is 24*48=1152Kbps) in real time, and Tx/RX the compressed data using 2.4G wireless, latency equal or less than 3ms, the max wireless speed is about 500Kbps, so we need compress rate 3:1 or 4:1, that is lossy codec. I tried adpcm souce, but the frequency spectrum analysis showing mang high frequency distortion. I want to do this using subband adpcm or other algorithms. are there any open source project concerning about this 24bit compress, or some papers i can reference?
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saratoga
post Nov 26 2010, 05:57
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QUOTE (yg2003618 @ Nov 25 2010, 21:09) *
thanks everyone, my project is using an ARM7 cpu to compress and decompress HiFi audio/music(24bit 48K sample rate that is 24*48=1152Kbps) in real time, and Tx/RX the compressed data using 2.4G wireless, latency equal or less than 3ms, the max wireless speed is about 500Kbps, so we need compress rate 3:1 or 4:1, that is lossy codec. I tried adpcm souce, but the frequency spectrum analysis showing mang high frequency distortion. I want to do this using subband adpcm or other algorithms. are there any open source project concerning about this 24bit compress, or some papers i can reference?


3ms latency rules out pretty much any mainstream format (including AAC and MP3). Does it need to be free? Apt-X has a very low latency subband codec, perhaps they'll sell you something if you're on a commercial product. Otherwise some kind of ADPCM or custom subband codec might be your best bet.
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yg2003618
post Nov 26 2010, 07:17
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QUOTE (saratoga @ Nov 26 2010, 06:57) *
QUOTE (yg2003618 @ Nov 25 2010, 21:09) *
thanks everyone, my project is using an ARM7 cpu to compress and decompress HiFi audio/music(24bit 48K sample rate that is 24*48=1152Kbps) in real time, and Tx/RX the compressed data using 2.4G wireless, latency equal or less than 3ms, the max wireless speed is about 500Kbps, so we need compress rate 3:1 or 4:1, that is lossy codec. I tried adpcm souce, but the frequency spectrum analysis showing mang high frequency distortion. I want to do this using subband adpcm or other algorithms. are there any open source project concerning about this 24bit compress, or some papers i can reference?


3ms latency rules out pretty much any mainstream format (including AAC and MP3). Does it need to be free? Apt-X has a very low latency subband codec, perhaps they'll sell you something if you're on a commercial product. Otherwise some kind of ADPCM or custom subband codec might be your best bet.


Otherwise some kind of ADPCM or custom subband codec might be your best bet. ?

could you please tell more?
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Posts in this topic
- yg2003618   24bit PCM compress   Nov 25 2010, 10:22
- - Engelsstaub   You can use dBpoweramp or Foobar 2000. I'm cer...   Nov 25 2010, 10:37
|- - googlebot   QUOTE (Engelsstaub @ Nov 25 2010, 10:37) ...   Nov 25 2010, 11:12
|- - Engelsstaub   QUOTE (googlebot @ Nov 25 2010, 04:12) QU...   Nov 25 2010, 23:15
|- - googlebot   QUOTE (Engelsstaub @ Nov 25 2010, 23:15) ...   Nov 26 2010, 01:07
- - soiaf   WavPack (lossy/hybrid mode) will certainly handle ...   Nov 25 2010, 22:27
- - romor   ^ Can you believe this guy? Is that old D.R.I. log...   Nov 25 2010, 23:55
|- - Engelsstaub   QUOTE (romor @ Nov 25 2010, 16:55) ^ Can ...   Nov 26 2010, 04:14
- - yg2003618   thanks everyone, my project is using an ARM7 cpu t...   Nov 26 2010, 03:09
|- - saratoga   QUOTE (yg2003618 @ Nov 25 2010, 21:09) th...   Nov 26 2010, 05:57
|- - yg2003618   QUOTE (saratoga @ Nov 26 2010, 06:57) QUO...   Nov 26 2010, 07:17
|- - saratoga   QUOTE (yg2003618 @ Nov 26 2010, 01:17) QU...   Nov 26 2010, 16:59
- - yg2003618   Nero AAC may do 24bit compress, but i need source ...   Nov 26 2010, 03:20
- - Engelsstaub   Doesn't compressing a 24-bit file to a lossy c...   Nov 26 2010, 09:32
|- - knutinh   QUOTE (Engelsstaub @ Nov 26 2010, 09:32) ...   Nov 26 2010, 11:16
|- - googlebot   QUOTE (Engelsstaub @ Nov 26 2010, 09:32) ...   Nov 26 2010, 19:56
|- - knutinh   QUOTE (googlebot @ Nov 26 2010, 19:56) Wh...   Nov 26 2010, 20:56
- - Engelsstaub   Thanks for the explanation, knutinh. I failed to ...   Nov 26 2010, 14:52
- - [JAZ]   Mmm... 1152kbps for 24bit 48Khz is a mono signal. ...   Nov 26 2010, 19:10
- - googlebot   It depends, if high dynamic range is a top priorit...   Nov 26 2010, 21:26
|- - saratoga   QUOTE (googlebot @ Nov 26 2010, 15:26) It...   Nov 26 2010, 21:42
|- - googlebot   QUOTE (saratoga @ Nov 26 2010, 21:42) I t...   Nov 26 2010, 21:54
|- - saratoga   QUOTE (googlebot @ Nov 26 2010, 15:54) Co...   Nov 26 2010, 22:39
- - googlebot   I've read it again. Maybe you are right. Even ...   Nov 26 2010, 23:43
- - yg2003618   CELT is the answer! thank you, thank you every...   Nov 27 2010, 00:48


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