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path: root/sound/firewire/tascam/amdtp-tascam.c
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2017-05-22ALSA: firewire: remove support for 16 bit PCM samples in playback substreamTakashi Sakamoto
In IEC 61883-6, AM824 is described as format of data block. In this format, one data block consists of several data channels, which is aligned to 32 bit. One data channel has 8 bit label field and 24 bit data field. PCM frames are transferred in Multi Bit Linear Audio (MBLA) data channel. This channel can include 16/20/24 bit PCM sample. As long as I know, models which support IEC 61883-1/6 doesn't allow to switch bit length of PCM sample in MBLA data channel. They always transmit/receive PCM frames of 24 bit length. This can be seen for the other models which support protocols similar to IEC 61883-1/6. On the other hand, current drivers for these protocols supports 16 bit length PCM sample in playback substream. In this case, PCM sample is put into the MBLA data channel with 8 bit padding in LSB side. Although 16 bit PCM sample is major because it's in CD format, this doesn't represent device capability as is. This commit removes support for 16 bit PCM samples in playback substream. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Acked-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
2015-10-02ALSA: firewire-tascam: add data block processing layerTakashi Sakamoto
TASCAM FireWire series uses non-blocking transmission for AMDTP packet streaming, while the format of data blocks is unique. The CIP headers includes specific value in FMT field and no SYT information. In transmitted packets, the first data channel represents event counter, and the last data channel has status and control information. The rest has 24bit PCM samples with right padding. In received packets, all of data channels include 16, 24, 32bit PCM samples. There's no other kind of information. This commit adds support for this protocol. For convenience, the size of PCM samples in outgoing packet is limited by 16 and 24bit. The status and control information will be supported in future commits. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>