On Fri, 17 Jun 2016, Anssi Hannula wrote: > 17.06.2016, 16:29, Mark Hills kirjoitti: > > Hi, > > Hi, > > > Is there any provision in ALSA (either within the kernel or libasound) for > > extracting track marker information from S/PDIF? > > I don't know what track marker data looks like, but see below. > > > I have a large number of MiniDisc recordings to preserve as FLAC format. > > > > Losing track markers would be a huge inconvenience, though I don't care > > for the rest of the metadata (track names etc..) > > > > There's enough recordings to be worth developing specific software for the > > archival if it can access this information. > > > > I don't really know which path is likely to be successful: > > > > * An ALSA API to access the information; though I can't see anything > > specific to track markers > > > > * Whether a timecode could be used to detect track change; but I can't see > > any in /proc/asound/Layla3G/status > > > > * Does ALSA provide access to raw AES streams, so I could decode it in > > userland? I'm un-sure if this relates to hardware AC3 decoding. > > ALSA does provide access to the raw stream with drivers that support > that. You'll need to record with IEC958_SUBFRAME_LE or > IEC958_SUBFRAME_BE sample formats. Thanks, that's very useful information. > > * Maybe this sort of status is only available to the firmware of the > > interface and never makes it to userland (in my case, echo3g); though I > > can see some constants relating to 'non audio' S/PDIF. > > Unfortunately the echo3g driver doesn't seem to support > IEC958_SUBFRAME_* sample formats. Ah, as I'd suspect. And probably there is a lot of logic in the firmware that would have to cooperate. > The HDA driver, used for most mainboard/laptop integrated audio, does > support that format if the hardware is capable. I'm not sure if the > hardware commonly supports that format or not, though. This is the hardware I have on my motherboard, but it doesn't have the optical input I would need. Perhaps I can find a reasonably priced PCI Express card with the capability. Thanks for your help, I have a feeling this is the most promising route. But it does assume the MiniDisc deck is outputting this information (it definitely acknoledges it on input) > > The hardware I have here is Echo Layla 3G (snd-echo3g) and a Pioneer > > MJ-D707 MiniDisc recorder. > > > > Any advice appreciated -- many thanks. Thanks -- Mark _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
