At Mon, 12 Feb 2007 12:34:04 +0100, Clemens Ladisch wrote: > > Takashi Iwai wrote: > > Lee Revell wrote: > > > On 2/6/07, Takashi Iwai <tiwai@xxxxxxx> wrote: > > > > Add the following line in the slave block > > > > > > > > format S32_LE > > > > > > > > Currently, the default format of direct plugins is S16, and most of > > > > ice1712 boards support only 32bit format. > > > > > > Takashi-san, > > > > > > This raises an interesting question - how can AC3 passthrough work on > > > these devices? mplayer and other apps fail because they can't set > > > S16_LE. > > > > It works simply by wrapping with plug (or linear) layer. > > I thought mplayer already puts that... > > Only when it's playing floating point samples. I'll change that. Hm, I thought it doesn't matter whether it's float or not, since only upper 16bit is referred in 32bit frames. (I remember AC3-passthru worked well with my ice1712 boards.) > > I myself think it's incer to add a format conversion as default in the > > iec958 PCM definition although other may think differently. > > Not having such a conversion means that applications have to remember > that they might have to put a "plug:" in front when they want to do > things like AC-3 or 5.1 output. Right. IIRC, the couter argument against the defalut plug is that we provide "iec958" PCM as a kind of raw device. This means, OTOH, that the apps get more burden. (Also, one another reason is that there is a known bug in alsa-lib that plug over plug (more exactly route over router) doesn't work well...) IMO, the design of alsa-lib subsystems are often too lowlevel. It's an interesting experiment, but a bad choice in the end in most cases. At least, "easy-to-do" setups have to be provided at the same time even if we offer primally lowlevel and raw interfaces. Takashi ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
