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dpcm: remove unnecessary variable by using bytestream functions. 

Uses 'buf' directly instead of a separate iterator variable 'in'.
This commit is contained in:
Justin Ruggles 2011-09-11 12:24:03 -04:00
parent fc6faee0d1
commit 1de8401c56
1 changed files with 28 additions and 38 deletions
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66
libavcodec/dpcm.c
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@ -39,6 +39,7 @@
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "bytestream.h"
typedef struct DPCMContext {
int channels;
@ -47,8 +48,6 @@ typedef struct DPCMContext {
const int *sol_table;//for SOL_DPCM
} DPCMContext;
#define SE_16BIT(x) if (x & 0x8000) x -= 0x10000;
static const int interplay_delta_table[] = {
0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15,
@ -169,8 +168,9 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
const uint8_t *buf_end = buf + buf_size;
DPCMContext *s = avctx->priv_data;
int in, out = 0;
int out = 0;
int predictor[2];
int ch = 0;
int stereo = s->channels - 1;
@ -207,18 +207,18 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
switch(avctx->codec->id) {
case CODEC_ID_ROQ_DPCM:
buf += 6;
if (stereo) {
predictor[0] = buf[7] << 8;
predictor[1] = buf[6] << 8;
predictor[1] = (int16_t)(bytestream_get_byte(&buf) << 8);
predictor[0] = (int16_t)(bytestream_get_byte(&buf) << 8);
} else {
predictor[0] = AV_RL16(&buf[6]);
predictor[0] = (int16_t)bytestream_get_le16(&buf);
}
SE_16BIT(predictor[0]);
SE_16BIT(predictor[1]);
/* decode the samples */
for (in = 8; in < buf_size; in++) {
predictor[ch] += s->roq_square_array[buf[in]];
while (buf < buf_end) {
predictor[ch] += s->roq_square_array[*buf++];
predictor[ch] = av_clip_int16(predictor[ch]);
*output_samples++ = predictor[ch];
@ -228,20 +228,16 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
break;
case CODEC_ID_INTERPLAY_DPCM:
in = 6; /* skip over the stream mask and stream length */
predictor[0] = AV_RL16(&buf[in]);
in += 2;
SE_16BIT(predictor[0])
*output_samples++ = predictor[0];
if (stereo) {
predictor[1] = AV_RL16(&buf[in]);
in += 2;
SE_16BIT(predictor[1])
*output_samples++ = predictor[1];
buf += 6; /* skip over the stream mask and stream length */
for (ch = 0; ch < s->channels; ch++) {
predictor[ch] = (int16_t)bytestream_get_le16(&buf);
*output_samples++ = predictor[ch];
}
while (in < buf_size) {
predictor[ch] += interplay_delta_table[buf[in++]];
ch = 0;
while (buf < buf_end) {
predictor[ch] += interplay_delta_table[*buf++];
predictor[ch] = av_clip_int16(predictor[ch]);
*output_samples++ = predictor[ch];
@ -253,18 +249,13 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
case CODEC_ID_XAN_DPCM:
{
int shift[2] = { 4, 4 };
in = 0;
predictor[0] = AV_RL16(&buf[in]);
in += 2;
SE_16BIT(predictor[0]);
if (stereo) {
predictor[1] = AV_RL16(&buf[in]);
in += 2;
SE_16BIT(predictor[1]);
}
while (in < buf_size) {
uint8_t n = buf[in++];
for (ch = 0; ch < s->channels; ch++)
predictor[ch] = (int16_t)bytestream_get_le16(&buf);
ch = 0;
while (buf < buf_end) {
uint8_t n = *buf++;
int16_t diff = (n & 0xFC) << 8;
if ((n & 0x03) == 3)
shift[ch]++;
@ -286,11 +277,10 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
break;
}
case CODEC_ID_SOL_DPCM:
in = 0;
if (avctx->codec_tag != 3) {
uint8_t *output_samples_u8 = data;
while (in < buf_size) {
uint8_t n = buf[in++];
while (buf < buf_end) {
uint8_t n = *buf++;
s->sample[0] += s->sol_table[n >> 4];
s->sample[0] = av_clip_uint8(s->sample[0]);
@ -301,8 +291,8 @@ static int dpcm_decode_frame(AVCodecContext *avctx,
*output_samples_u8++ = s->sample[stereo];
}
} else {
while (in < buf_size) {
uint8_t n = buf[in++];
while (buf < buf_end) {
uint8_t n = *buf++;
if (n & 0x80) s->sample[ch] -= s->sol_table[n & 0x7F];
else s->sample[ch] += s->sol_table[n & 0x7F];
s->sample[ch] = av_clip_int16(s->sample[ch]);