---------- Forwarded message ---------- From: Michael Bourgeous <sts.nitrogen@xxxxxxxxx> Date: Feb 28, 2007 1:30 AM Subject: Re: Home Theatre PC to Decode Digital Input To: "Dustin C. Hatch" <admiralnemo@xxxxxxxxxx> You could probably do some research on how AC3-wavs and AC3 CDs are made, then do the reverse on the recorded raw digital sound (possibly using "iec958" as the recording device, if that device is full duplex). You could then pipe the raw ac3 data into ac3dec/a52dec. Unless your sound card synchronizes its clock to the S/PDIF input, you will have annoying sync problems. There may also be some decoding latency introduced by the record/playback process, which could be minimized by writing your own tool that would open the sound card with the smallest possible record and playback buffers, and use liba52 and libdts to decode the audio. You could then throw in some resampling code to try to keep sync, though if your card doesn't sync to its digital input the AC3 stream will probably be ruined by the card's sample rate conversion (even 47.9kHz->48kHz conversion caused by minor clock discrepancies would ruin it). If you implement this, please share your method and results. Mike Bourgeous On 2/27/07, Dustin C. Hatch <admiralnemo@xxxxxxxxxx> wrote: > > Hello, > > I hope this is the correct place to ask this question. I have been > researching for several months and I cannot seem to find a definitive > answer, so I thought I would give this list a try. > > I am planning to build a home theatre system with 5/7.1 surround sound. It > will have a high-definition plasma television, DVD-player, and CD player, > all of which have S/PDIF outputs. Rather than purchase a prefabricated > "receiver," I would like to use a Linux-based personal computer to perform > the decoding of the S/PDIF into 6 or 8 analog channels to send to the > amplifiers. I have been searching for quite some time and I am unable to > make an educated decision regarding this possibility. > > Are there any ALSA drivers that will decode AC-3 S/PDIF input (coaxial or > optical) and pipe the analog sound to the proper outputs? If so, which are > recommended? I hope you can provide some insight to this possibility. I > would much rather use an open-source computer to perform my functions than a > hardware decoder. > > If anyone has any suggestions, please let me know. > > Thanks, > -- > Dustin C. Hatch > http://www.dchweb.com > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > Alsa-user mailing list > Alsa-user@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/alsa-user > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
