From 01880d287be6e2269b92eee8d9dc442532d277ea Mon Sep 17 00:00:00 2001 From: Justin Ruggles Date: Mon, 9 Jul 2012 11:12:25 -0400 Subject: alac: simplify 1st order prediction and reading of warm-up samples --- libavcodec/alac.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) (limited to 'libavcodec/alac.c') diff --git a/libavcodec/alac.c b/libavcodec/alac.c index 9a3ca51054..b19973db50 100644 --- a/libavcodec/alac.c +++ b/libavcodec/alac.c @@ -186,25 +186,17 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer, /* simple 1st-order prediction */ if (output_size <= 1) return; - for (i = 0; i < output_size - 1; i++) { - int32_t prev_value; - int32_t error_value; - - prev_value = buffer_out[i]; - error_value = error_buffer[i+1]; - buffer_out[i+1] = - sign_extend((prev_value + error_value), readsamplesize); + for (i = 1; i < output_size; i++) { + buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], + readsamplesize); } return; } /* read warm-up samples */ for (i = 0; i < predictor_coef_num; i++) { - int32_t val; - - val = buffer_out[i] + error_buffer[i+1]; - val = sign_extend(val, readsamplesize); - buffer_out[i+1] = val; + buffer_out[i + 1] = sign_extend(buffer_out[i] + error_buffer[i + 1], + readsamplesize); } /* NOTE: 4 and 8 are very common cases that could be optimized. */ -- cgit v1.2.3