Hello.

I'd like to play a wav file converted from S24_3LE format to S24_LE by alsa-lib. (I use aplay command.)

I recognize the following:

<PCM format in wav file> ex. Valid PCM data is 0x123456.

S24_LE : 0x12345600(in 4bytes, LSB 0 padding) S24_3LE : 0x123456 (in 3bytes, No padding)

When the S24_LE format file is played, the ALSA driver receives data format is as follows:

0x12345600 (LSB 0 padding)

However, when the S24_3LE format file which is converted to S24_LE by alsa-lib is played, the ALSA driver receives data formats is as follows:

0x00123456 (MSB 0(or 0xFF) padding)

Why is the how to pad 0 different(LSB/MSB)?

cf.

When "snd_pcm_linear_getput" is called 'get_idx' is set 16. 'put_idx' is set 8.

[alsa-lib:pcm_linear.c]

211 void snd_pcm_linear_getput(const snd_pcm_channel_area_t *dst_areas, snd_ pcm_uframes_t dst_offset, 212 const snd_pcm_channel_area_t *src_areas, snd_ pcm_uframes_t src_offset, 213 unsigned int channels, snd_pcm_uframes_t fram es, 214 unsigned int get_idx, unsigned int put_idx) 215 { 216 #define CONV24_LABELS 217 #include "plugin_ops.h" 218 #undef CONV24_LABELS 219 void *get = get32_labels[get_idx]; 220 void *put = put32_labels[put_idx]; 221 unsigned int channel; 222 u_int32_t sample = 0; 223 for (channel = 0; channel < channels; ++channel) { 224 const char *src;

When 'get_idx' is 16 and 'put_idx' is 8, it is converted as follows:

0x123456(S24_3LE) -> 0x00123456(MSB 0 padding)

I expect the following:

0x123456(S24_3LE) -> 0x12345600(LSB 0 padding)

(If 'get_idx' is 16 and 'put_idx' is 12, it is converted like this.)

I'm doing something wrong?

-------------------- alsa-lib-1.0.24.1 alsa-utils-1.0.24.2 --------------------

Regards.

Kaz