Performance optimizations for input data processing in SBC encoder

Channels deinterleaving, endian conversion and samples reordering
is done in one pass, avoiding the use of intermediate buffer. Also
this code is implemented as a new "performance primitive", which
allows further platform specific optimizations (ARMv6 and ARM NEON
should gain quite a lot from assembly optimizations here).

1 files changed, 29 insertions, 26 deletions

diff --git a/sbc/sbc.c b/sbc/sbc.c
index 190ac17f..365ee1ff 100644
--- a/sbc/sbc.c
+++ b/sbc/sbc.c
@@ -657,14 +657,11 @@ static int sbc_analyze_audio(struct sbc_encoder_state *state,
 		for (ch = 0; ch < frame->channels; ch++)
 			for (blk = 0; blk < frame->blocks; blk += 4) {
 				state->sbc_analyze_4b_4s(
-					&frame->pcm_sample[ch][blk * 4],
-					&state->X[ch][state->position[ch]],
+					&state->X[ch][state->position +
+							48 - blk * 4],
 					frame->sb_sample_f[blk][ch],
 					frame->sb_sample_f[blk + 1][ch] -
 					frame->sb_sample_f[blk][ch]);
-				state->position[ch] -= 16;
-				if (state->position[ch] < 0)
-					state->position[ch] = 64 - 16;
 			}
 		return frame->blocks * 4;
 
@@ -672,14 +669,11 @@ static int sbc_analyze_audio(struct sbc_encoder_state *state,
 		for (ch = 0; ch < frame->channels; ch++)
 			for (blk = 0; blk < frame->blocks; blk += 4) {
 				state->sbc_analyze_4b_8s(
-					&frame->pcm_sample[ch][blk * 8],
-					&state->X[ch][state->position[ch]],
+					&state->X[ch][state->position +
+							96 - blk * 8],
 					frame->sb_sample_f[blk][ch],
 					frame->sb_sample_f[blk + 1][ch] -
 					frame->sb_sample_f[blk][ch]);
-				state->position[ch] -= 32;
-				if (state->position[ch] < 0)
-					state->position[ch] = 128 - 32;
 			}
 		return frame->blocks * 8;
 
@@ -935,8 +929,7 @@ static void sbc_encoder_init(struct sbc_encoder_state *state,
 				const struct sbc_frame *frame)
 {
 	memset(&state->X, 0, sizeof(state->X));
-	state->subbands = frame->subbands;
-	state->position[0] = state->position[1] = 12 * frame->subbands;
+	state->position = SBC_X_BUFFER_SIZE - frame->subbands * 9;
 
 	sbc_init_primitives(state);
 }
@@ -1060,8 +1053,10 @@ int sbc_encode(sbc_t *sbc, void *input, int input_len, void *output,
 		int output_len, int *written)
 {
 	struct sbc_priv *priv;
-	char *ptr;
-	int i, ch, framelen, samples;
+	int framelen, samples;
+	int (*sbc_enc_process_input)(int position,
+			const uint8_t *pcm, int16_t X[2][SBC_X_BUFFER_SIZE],
+			int nsamples, int nchannels);
 
 	if (!sbc && !input)
 		return -EIO;
@@ -1096,20 +1091,28 @@ int sbc_encode(sbc_t *sbc, void *input, int input_len, void *output,
 	if (!output || output_len < priv->frame.length)
 		return -ENOSPC;
 
-	ptr = input;
-
-	for (i = 0; i < priv->frame.subbands * priv->frame.blocks; i++) {
-		for (ch = 0; ch < priv->frame.channels; ch++) {
-			int16_t s;
-			if (sbc->endian == SBC_BE)
-				s = (ptr[0] & 0xff) << 8 | (ptr[1] & 0xff);
-			else
-				s = (ptr[0] & 0xff) | (ptr[1] & 0xff) << 8;
-			ptr += 2;
-			priv->frame.pcm_sample[ch][i] = s;
-		}
+	/* Select the needed input data processing function and call it */
+	if (priv->frame.subbands == 8) {
+		if (sbc->endian == SBC_BE)
+			sbc_enc_process_input =
+				priv->enc_state.sbc_enc_process_input_8s_be;
+		else
+			sbc_enc_process_input =
+				priv->enc_state.sbc_enc_process_input_8s_le;
+	} else {
+		if (sbc->endian == SBC_BE)
+			sbc_enc_process_input =
+				priv->enc_state.sbc_enc_process_input_4s_be;
+		else
+			sbc_enc_process_input =
+				priv->enc_state.sbc_enc_process_input_4s_le;
 	}
 
+	priv->enc_state.position = sbc_enc_process_input(
+		priv->enc_state.position, (const uint8_t *) input,
+		priv->enc_state.X, priv->frame.subbands * priv->frame.blocks,
+		priv->frame.channels);
+
 	samples = sbc_analyze_audio(&priv->enc_state, &priv->frame);
 
 	framelen = sbc_pack_frame(output, &priv->frame, output_len);