15.08.2014 12:43, Jurgen Kramer wrote:

Functions 'snd_pcm_format_silence_64' and 'snd_pcm_format_size' also need to be able to handle the DSD formats.

0 is not a DSD silence value. It is the most negative value, similar to -32768 for S16 samples. We need something that will average to zero.

ffmpeg uses a repeating pattern of 0x69 here, with this comment:

/* 0x69 = 01101001 * This pattern "on repeat" makes a low energy 352.8 kHz tone * and a high energy 1.0584 MHz tone which should be filtered * out completely by any playback system --> silence */

https://ffmpeg.org/pipermail/ffmpeg-cvslog/2014-April/076427.html

Signed-off-by: Jurgen Kramer gtmkramer@xs4all.nl

src/pcm/pcm_misc.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/src/pcm/pcm_misc.c b/src/pcm/pcm_misc.c index 24d52f9..c52e7bf 100644 --- a/src/pcm/pcm_misc.c +++ b/src/pcm/pcm_misc.c @@ -317,11 +317,13 @@ ssize_t snd_pcm_format_size(snd_pcm_format_t format, size_t samples) switch (format) { case SNDRV_PCM_FORMAT_S8: case SNDRV_PCM_FORMAT_U8:

• case SNDRV_PCM_FORMAT_DSD_U8: return samples; case SNDRV_PCM_FORMAT_S16_LE: case SNDRV_PCM_FORMAT_S16_BE: case SNDRV_PCM_FORMAT_U16_LE: case SNDRV_PCM_FORMAT_U16_BE:
• case SNDRV_PCM_FORMAT_DSD_U16_LE: return samples * 2; case SNDRV_PCM_FORMAT_S18_3LE: case SNDRV_PCM_FORMAT_S18_3BE:

@@ -387,6 +389,8 @@ u_int64_t snd_pcm_format_silence_64(snd_pcm_format_t format) case SNDRV_PCM_FORMAT_S20_3BE: case SNDRV_PCM_FORMAT_S18_3LE: case SNDRV_PCM_FORMAT_S18_3BE:

• case SNDRV_PCM_FORMAT_DSD_U8:
• case SNDRV_PCM_FORMAT_DSD_U16_LE: return 0; case SNDRV_PCM_FORMAT_U8: return 0x8080808080808080ULL;