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| author | Siarhei Siamashka <siarhei.siamashka@nokia.com> | 2011-03-14 15:07:38 -0300 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.dentz-von@nokia.com> | 2011-03-14 15:07:38 -0300 |
| commit | 84d91fb7084118730229fb83e2fc5479bc8f35f2 (patch) | |
| tree | 2835a50792ca7ec729a2bee7d32aafe4dc233609 | |
| parent | 4d2f0daba17617bb60e0bd40f7a0329181dc09e4 (diff) | |
| download | pulseaudio-panda-84d91fb7084118730229fb83e2fc5479bc8f35f2.tar.gz pulseaudio-panda-84d91fb7084118730229fb83e2fc5479bc8f35f2.tar.bz2 pulseaudio-panda-84d91fb7084118730229fb83e2fc5479bc8f35f2.zip | |
sbc: added saturated clipping of decoder output to 16-bit
This prevents overflows and audible artefacts for the audio files which
originally had loudness maximized. Music from audio CD disks is an
example of such files, see http://en.wikipedia.org/wiki/Loudness_war
| -rw-r--r-- | src/modules/bluetooth/sbc/sbc.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/src/modules/bluetooth/sbc/sbc.c b/src/modules/bluetooth/sbc/sbc.c index 5c546ca8..3af0a03c 100644 --- a/src/modules/bluetooth/sbc/sbc.c +++ b/src/modules/bluetooth/sbc/sbc.c @@ -534,6 +534,16 @@ static void sbc_decoder_init(struct sbc_decoder_state *state, state->offset[ch][i] = (10 * i + 10); } +static SBC_ALWAYS_INLINE int16_t sbc_clip16(int32_t s) +{ + if (s > 0x7FFF) + return 0x7FFF; + else if (s < -0x8000) + return -0x8000; + else + return s; +} + static inline void sbc_synthesize_four(struct sbc_decoder_state *state, struct sbc_frame *frame, int ch, int blk) { @@ -562,7 +572,7 @@ static inline void sbc_synthesize_four(struct sbc_decoder_state *state, k = (i + 4) & 0xf; /* Store in output, Q0 */ - frame->pcm_sample[ch][blk * 4 + i] = SCALE4_STAGED1( + frame->pcm_sample[ch][blk * 4 + i] = sbc_clip16(SCALE4_STAGED1( MULA(v[offset[i] + 0], sbc_proto_4_40m0[idx + 0], MULA(v[offset[k] + 1], sbc_proto_4_40m1[idx + 0], MULA(v[offset[i] + 2], sbc_proto_4_40m0[idx + 1], @@ -572,7 +582,7 @@ static inline void sbc_synthesize_four(struct sbc_decoder_state *state, MULA(v[offset[i] + 6], sbc_proto_4_40m0[idx + 3], MULA(v[offset[k] + 7], sbc_proto_4_40m1[idx + 3], MULA(v[offset[i] + 8], sbc_proto_4_40m0[idx + 4], - MUL( v[offset[k] + 9], sbc_proto_4_40m1[idx + 4]))))))))))); + MUL( v[offset[k] + 9], sbc_proto_4_40m1[idx + 4])))))))))))); } } @@ -607,8 +617,8 @@ static inline void sbc_synthesize_eight(struct sbc_decoder_state *state, for (idx = 0, i = 0; i < 8; i++, idx += 5) { k = (i + 8) & 0xf; - /* Store in output */ - frame->pcm_sample[ch][blk * 8 + i] = SCALE8_STAGED1( // Q0 + /* Store in output, Q0 */ + frame->pcm_sample[ch][blk * 8 + i] = sbc_clip16(SCALE8_STAGED1( MULA(state->V[ch][offset[i] + 0], sbc_proto_8_80m0[idx + 0], MULA(state->V[ch][offset[k] + 1], sbc_proto_8_80m1[idx + 0], MULA(state->V[ch][offset[i] + 2], sbc_proto_8_80m0[idx + 1], @@ -618,7 +628,7 @@ static inline void sbc_synthesize_eight(struct sbc_decoder_state *state, MULA(state->V[ch][offset[i] + 6], sbc_proto_8_80m0[idx + 3], MULA(state->V[ch][offset[k] + 7], sbc_proto_8_80m1[idx + 3], MULA(state->V[ch][offset[i] + 8], sbc_proto_8_80m0[idx + 4], - MUL( state->V[ch][offset[k] + 9], sbc_proto_8_80m1[idx + 4]))))))))))); + MUL( state->V[ch][offset[k] + 9], sbc_proto_8_80m1[idx + 4])))))))))))); } } |