Re: [PATCH] cmipci - allow capture of raw spdif subframes

Re: [PATCH] cmipci - allow capture of raw spdif subframes

[Takashi Iwai]

At Wed, 07 Nov 2007 15:12:46 +0300,
Timofei V. Bondarenko wrote:
> 
> Hi.
> 
> Enable capturing of raw 32bit IEC958_SUBFRAME.
> 
> The 24-bits PCM data can be obtained using iec958 plugin.
> 
> Known problem: captured stream may begin with either left or right 
> subframe. Since the iec958 plugin doesn't decode preamble it may swap 
> the channels sometime.
> 
> Regards,
> 	Tim.

Applied this one, too.
(Do you happen to have a fix for iec958 plugin, too? :)


Thanks,

Takashi

[PATCH] cmipci - allow capture of raw spdif subframes

[Timofei V. Bondarenko]

Hi.

Enable capturing of raw 32bit IEC958_SUBFRAME.

The 24-bits PCM data can be obtained using iec958 plugin.

Known problem: captured stream may begin with either left or right 
subframe. Since the iec958 plugin doesn't decode preamble it may swap 
the channels sometime.

Regards,
	Tim.

Re: [PATCH] cmipci - allow capture of raw spdif subframes

[Timofei V. Bondarenko]

[-- Attachment #1: Type: text/plain, Size: 364 bytes --]

Timofei V. Bondarenko wrote:
> Hi.
> 
> Enable capturing of raw 32bit IEC958_SUBFRAME.
> 
> The 24-bits PCM data can be obtained using iec958 plugin.
> 
> Known problem: captured stream may begin with either left or right 
> subframe. Since the iec958 plugin doesn't decode preamble it may swap 
> the channels sometime.

Sorry, i've forgot to attach the patch...

[-- Attachment #2: cmi-capt-spdif24.patch --]
[-- Type: text/x-patch, Size: 1420 bytes --]

Signed-off-by: Timofei Bondarenko <tim@ipi.ac.ru>

--- alsa-driver-hg20071107/alsa-kernel/pci/cmipci.c	2007-11-01 04:00:07.000000000 +0300
+++ alsa-driver/alsa-kernel/pci/cmipci.c	2007-11-07 14:55:05.000000000 +0300
@@ -1400,6 +1407,11 @@ static int snd_cmipci_capture_spdif_prep
 		else
 			snd_cmipci_clear_bit(cm, CM_REG_CHFORMAT, CM_DBLSPDS);
 	}
+	if (snd_pcm_format_width(substream->runtime->format) > 16)
+		snd_cmipci_set_bit(cm, CM_REG_MISC_CTRL, CM_SPD32SEL);
+	else
+		snd_cmipci_clear_bit(cm, CM_REG_MISC_CTRL, CM_SPD32SEL);
+
 	spin_unlock_irq(&cm->reg_lock);
 
 	return snd_cmipci_pcm_prepare(cm, &cm->channel[CM_CH_CAPT], substream);
@@ -1411,6 +1423,7 @@ static int snd_cmipci_capture_spdif_hw_f
 
 	spin_lock_irq(&cm->reg_lock);
 	snd_cmipci_clear_bit(cm, CM_REG_FUNCTRL1, CM_CAPTURE_SPDF);
+	snd_cmipci_clear_bit(cm, CM_REG_MISC_CTRL, CM_SPD32SEL);
 	spin_unlock_irq(&cm->reg_lock);
 
 	return snd_cmipci_hw_free(subs);
@@ -1562,7 +1575,8 @@ static struct snd_pcm_hardware snd_cmipc
 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
 				 SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_PAUSE |
 				 SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_MMAP_VALID),
-	.formats =	        SNDRV_PCM_FMTBIT_S16_LE,
+	.formats =	        SNDRV_PCM_FMTBIT_S16_LE |
+				SNDRV_PCM_FMTBIT_IEC958_SUBFRAME_LE,
 	.rates =		SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
 	.rate_min =		44100,
 	.rate_max =		48000,

[-- Attachment #3: Type: text/plain, Size: 160 bytes --]

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Re: [PATCH] cmipci - allow capture of raw spdif subframes

[Takashi Iwai]

At Tue, 13 Nov 2007 16:47:38 +0300,
Timofei V. Bondarenko wrote:
> 
> Takashi Iwai wrote:
> > At Wed, 07 Nov 2007 15:12:46 +0300,
> > Timofei V. Bondarenko wrote:
> >> Hi.
> >>
> >> Enable capturing of raw 32bit IEC958_SUBFRAME.
> >>
> >> The 24-bits PCM data can be obtained using iec958 plugin.
> >>
> >> Known problem: captured stream may begin with either left or right 
> >> subframe. Since the iec958 plugin doesn't decode preamble it may swap 
> >> the channels sometime.
> >>
> >> Regards,
> >> 	Tim.
> > 
> > Applied this one, too.
> > (Do you happen to have a fix for iec958 plugin, too? :)
> 
> Not yet.
> I'm in doubt about a clean way to drop one subframe from the raw stream.
> Could you give me a hint?

It'll be tricky, yes.  We can prepend a zero in the first shot and
keep one pending channel data to shift.  For example,

  raw: R0 L0 R1 L1 R2 L2 ... R(n-1) L(n-1) | R(n) L(n) ... 
  dec: 0  R0 L0 R1 L1 R2 ... L(n-2) R(n-1) | L(n-1) R(n) ...


Takashi

Re: [PATCH] cmipci - allow capture of raw spdif subframes

[Timofei V. Bondarenko]

Takashi Iwai wrote:
> At Wed, 07 Nov 2007 15:12:46 +0300,
> Timofei V. Bondarenko wrote:
>> Hi.
>>
>> Enable capturing of raw 32bit IEC958_SUBFRAME.
>>
>> The 24-bits PCM data can be obtained using iec958 plugin.
>>
>> Known problem: captured stream may begin with either left or right 
>> subframe. Since the iec958 plugin doesn't decode preamble it may swap 
>> the channels sometime.
>>
>> Regards,
>> 	Tim.
> 
> Applied this one, too.
> (Do you happen to have a fix for iec958 plugin, too? :)

Not yet.
I'm in doubt about a clean way to drop one subframe from the raw stream.
Could you give me a hint?

Regards,
	Tim.