[alsa-devel] [PATCH] compress: add support for gapless playback

[Takashi Iwai]

At Thu, 14 Feb 2013 14:12:51 +0530,
Vinod Koul wrote:
> 
> this add new API for sound compress to support gapless playback.
> As noted in Documentation change, we add API to send metadata of encoder and
> padding delay to DSP. Also add API for indicating EOF and switching to
> subsequent track
> 
> Also bump the compress API version
> 
> Signed-off-by: Jeeja KP <jeeja.kp at intel.com>
> Signed-off-by: Vinod Koul <vinod.koul at intel.com>
> ---
>  v5:
> - update metadata value with 8 words

What's the reason behind this change?  I can think of metadata like EQ
parameters, but the magic number 8 is in question :)

I'm no enthusiastic over minimalism like Apple, so I don't mind this
change, but just out of curiosity...

Also, another spot:

> @@ -145,6 +160,10 @@ struct snd_compr_codec_caps {
>  						struct snd_compr_codec_caps)
>  #define SNDRV_COMPRESS_SET_PARAMS	_IOW('C', 0x12, struct snd_compr_params)
>  #define SNDRV_COMPRESS_GET_PARAMS	_IOR('C', 0x13, struct snd_codec)
> +#define SNDRV_COMPRESS_SET_METADATA	_IOW('C', 0x14,\
> +						 struct snd_compr_metadata)
> +#define SNDRV_COMPRESS_GET_METADATA	_IOW('C', 0x15,\
> +						 struct snd_compr_metadata)

Isn't it _IOWR()?


Takashi