mirrors/pipewire
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/pipewire/pipewire.git synced 2025-10-31 22:25:38 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

audioconvert: improve format conversion

Browse source 
Make dither noise as a value between -0.5 and 0.5 and add this
to the scaled samples.
For this, we first need to do the scaling and then the CLAMP to
the target depth. This optimizes to the same code but allows us
to avoid under and overflows when we add the dither noise.

Add more dithering methods.

Expose a dither.method property on audioconvert. Disable dither when
the target depth > 16.
This commit is contained in:
Wim Taymans 2022-06-29 14:10:15 +02:00
parent d23b96b033
commit 938f2b123e
6 changed files with 408 additions and 171 deletions
Download patch file Download diff file Expand all files Collapse all files

41
spa/plugins/audioconvert/fmt-ops.c
View file

@ -170,13 +170,17 @@ static struct conv_info conv_table[] =
/* from f32 */
MAKE(F32, U8, 0, conv_f32_to_u8_c),
MAKE(F32P, U8P, 0, conv_f32d_to_u8d_dither_c, 0, CONV_DITHER),
MAKE(F32P, U8P, 0, conv_f32d_to_u8d_c),
MAKE(F32, U8P, 0, conv_f32_to_u8d_c),
MAKE(F32P, U8, 0, conv_f32d_to_u8_dither_c, 0, CONV_DITHER),
MAKE(F32P, U8, 0, conv_f32d_to_u8_c),
MAKE(F32, S8, 0, conv_f32_to_s8_c),
MAKE(F32P, S8P, 0, conv_f32d_to_s8d_dither_c, 0, CONV_DITHER),
MAKE(F32P, S8P, 0, conv_f32d_to_s8d_c),
MAKE(F32, S8P, 0, conv_f32_to_s8d_c),
MAKE(F32P, S8, 0, conv_f32d_to_s8_dither_c, 0, CONV_DITHER),
MAKE(F32P, S8, 0, conv_f32d_to_s8_c),
MAKE(F32P, ALAW, 0, conv_f32d_to_alaw_c),
@ -224,7 +228,11 @@ static struct conv_info conv_table[] =
MAKE(F32P, S32P, 0, conv_f32d_to_s32d_c),
MAKE(F32, S32P, 0, conv_f32_to_s32d_c),
#if defined (HAVE_SSE2)
MAKE(F32P, S32, 0, conv_f32d_to_s32_dither_sse2, SPA_CPU_FLAG_SSE2, CONV_DITHER),
#endif
MAKE(F32P, S32, 0, conv_f32d_to_s32_dither_c, 0, CONV_DITHER),
#if defined (HAVE_AVX2)
MAKE(F32P, S32, 0, conv_f32d_to_s32_avx2, SPA_CPU_FLAG_AVX2),
#endif
@ -357,17 +365,38 @@ static void impl_convert_free(struct convert *conv)
conv->dither = NULL;
}
static bool need_dither(uint32_t format)
{
switch (format) {
case SPA_AUDIO_FORMAT_U8:
case SPA_AUDIO_FORMAT_U8P:
case SPA_AUDIO_FORMAT_S8:
case SPA_AUDIO_FORMAT_S8P:
case SPA_AUDIO_FORMAT_ULAW:
case SPA_AUDIO_FORMAT_ALAW:
case SPA_AUDIO_FORMAT_S16P:
case SPA_AUDIO_FORMAT_S16:
case SPA_AUDIO_FORMAT_S16_OE:
return true;
}
return false;
}
int convert_init(struct convert *conv)
{
const struct conv_info *info;
uint32_t i, shift, dither_flags;
uint32_t i, dither_flags;
shift = 24u - SPA_MIN(conv->quantize, 24u);
shift += conv->noise;
conv->scale = 1.0f / (float)(INT32_MAX >> conv->noise);
conv->mask = (1ULL << (shift + 1)) - 1;
conv->offset = shift < 32 ? -(1ULL << shift) : 0;
conv->bias = shift > 0 ? 1 << (shift - 1) : 0;
/* disable dither if not needed */
if (!need_dither(conv->dst_fmt))
conv->method = DITHER_METHOD_NONE;
/* don't use shaped for too low rates, it moves the noise to
* audible ranges */
if (conv->method == DITHER_METHOD_SHAPED_5 && conv->rate < 32000)
conv->method = DITHER_METHOD_TRIANGULAR;
dither_flags = 0;
if (conv->method != DITHER_METHOD_NONE || conv->noise)