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authorJustin Ruggles <justin.ruggles@gmail.com>2011-11-19 17:46:15 -0500
committerJustin Ruggles <justin.ruggles@gmail.com>2011-11-26 16:25:06 -0500
commit8db67610c016d1aa8ed09643b1ee9b96f7b18c01 (patch)
tree29d88dbe07906d3166cd21b009b6066a344690b0 /libavcodec/adxdec.c
parentfbc79a9101b9674327beba9c2a454163ead1e7a5 (diff)
downloadffmpeg-streaming-8db67610c016d1aa8ed09643b1ee9b96f7b18c01.zip
ffmpeg-streaming-8db67610c016d1aa8ed09643b1ee9b96f7b18c01.tar.gz
adx: cosmetics: general pretty-printing and comment clean-up
Diffstat (limited to 'libavcodec/adxdec.c')
-rw-r--r--libavcodec/adxdec.c134
1 files changed, 73 insertions, 61 deletions
diff --git a/libavcodec/adxdec.c b/libavcodec/adxdec.c
index 642d31d..7d06d27 100644
--- a/libavcodec/adxdec.c
+++ b/libavcodec/adxdec.c
@@ -38,82 +38,95 @@ static av_cold int adx_decode_init(AVCodecContext *avctx)
return 0;
}
-/* 18 bytes <-> 32 samples */
-
-static void adx_decode(int16_t *out,const unsigned char *in,
- ADXChannelState *prev)
+/**
+ * Decode 32 samples from 18 bytes.
+ *
+ * A 16-bit scalar value is applied to 32 residuals, which then have a
+ * 2nd-order LPC filter applied to it to form the output signal for a single
+ * channel.
+ */
+static void adx_decode(int16_t *out, const uint8_t *in, ADXChannelState *prev)
{
int scale = AV_RB16(in);
int i;
- int s0,s1,s2,d;
+ int s0, s1, s2, d;
- in+=2;
+ in += 2;
s1 = prev->s1;
s2 = prev->s2;
- for(i=0;i<16;i++) {
- d = in[i];
- d = ((signed char)d >> 4);
- s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
+ for (i = 0; i < 16; i++) {
+ d = in[i];
+ d = (signed char)d >> 4;
+ s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14;
s2 = s1;
s1 = av_clip_int16(s0);
- *out++=s1;
+ *out++ = s1;
- d = in[i];
- d = ((signed char)(d<<4) >> 4);
- s0 = (BASEVOL*d*scale + SCALE1*s1 - SCALE2*s2)>>14;
+ d = in[i];
+ d = (signed char)(d << 4) >> 4;
+ s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14;
s2 = s1;
s1 = av_clip_int16(s0);
- *out++=s1;
+ *out++ = s1;
}
prev->s1 = s1;
prev->s2 = s2;
-
}
-static void adx_decode_stereo(int16_t *out,const unsigned char *in,
+static void adx_decode_stereo(int16_t *out,const uint8_t *in,
ADXChannelState *prev)
{
short tmp[32*2];
int i;
- adx_decode(tmp ,in ,prev);
- adx_decode(tmp+32,in+18,prev+1);
- for(i=0;i<32;i++) {
- out[i*2] = tmp[i];
+ adx_decode(tmp, in, prev);
+ adx_decode(tmp+32, in+18, prev+1);
+ for (i = 0; i < 32; i++) {
+ out[i*2 ] = tmp[i ];
out[i*2+1] = tmp[i+32];
}
}
-/* return data offset or 0 */
-static int adx_decode_header(AVCodecContext *avctx,const unsigned char *buf,size_t bufsize)
+/**
+ * Decode stream header.
+ *
+ * @param avctx codec context
+ * @param buf packet data
+ * @param bufsize packet size
+ * @return data offset or 0 if header is invalid
+ */
+static int adx_decode_header(AVCodecContext *avctx, const uint8_t *buf,
+ int bufsize)
{
int offset;
- if (buf[0]!=0x80) return 0;
- offset = (AV_RB32(buf)^0x80000000)+4;
- if (bufsize<offset || memcmp(buf+offset-6,"(c)CRI",6)) return 0;
+ if (buf[0] != 0x80)
+ return 0;
+ offset = (AV_RB32(buf) ^ 0x80000000) + 4;
+ if (bufsize < offset || memcmp(buf + offset - 6, "(c)CRI", 6))
+ return 0;
avctx->channels = buf[7];
- avctx->sample_rate = AV_RB32(buf+8);
- avctx->bit_rate = avctx->sample_rate*avctx->channels*18*8/32;
+ avctx->sample_rate = AV_RB32(buf + 8);
+ avctx->bit_rate = avctx->sample_rate * avctx->channels * 18 * 8 / 32;
return offset;
}
-static int adx_decode_frame(AVCodecContext *avctx,
- void *data, int *data_size,
- AVPacket *avpkt)
+static int adx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
+ AVPacket *avpkt)
{
const uint8_t *buf0 = avpkt->data;
- int buf_size = avpkt->size;
- ADXContext *c = avctx->priv_data;
- int16_t *samples = data;
- const uint8_t *buf = buf0;
- int rest = buf_size;
+ int buf_size = avpkt->size;
+ ADXContext *c = avctx->priv_data;
+ int16_t *samples = data;
+ const uint8_t *buf = buf0;
+ int rest = buf_size;
if (!c->header_parsed) {
- int hdrsize = adx_decode_header(avctx,buf,rest);
- if (hdrsize==0) return -1;
+ int hdrsize = adx_decode_header(avctx, buf, rest);
+ if (!hdrsize)
+ return -1;
c->header_parsed = 1;
buf += hdrsize;
rest -= hdrsize;
@@ -121,46 +134,46 @@ static int adx_decode_frame(AVCodecContext *avctx,
/* 18 bytes of data are expanded into 32*2 bytes of audio,
so guard against buffer overflows */
- if(rest/18 > *data_size/64)
- rest = (*data_size/64) * 18;
+ if (rest / 18 > *data_size / 64)
+ rest = (*data_size / 64) * 18;
if (c->in_temp) {
- int copysize = 18*avctx->channels - c->in_temp;
- memcpy(c->dec_temp+c->in_temp,buf,copysize);
+ int copysize = 18 * avctx->channels - c->in_temp;
+ memcpy(c->dec_temp + c->in_temp, buf, copysize);
rest -= copysize;
buf += copysize;
- if (avctx->channels==1) {
- adx_decode(samples,c->dec_temp,c->prev);
+ if (avctx->channels == 1) {
+ adx_decode(samples, c->dec_temp, c->prev);
samples += 32;
} else {
- adx_decode_stereo(samples,c->dec_temp,c->prev);
+ adx_decode_stereo(samples, c->dec_temp, c->prev);
samples += 32*2;
}
}
- if (avctx->channels==1) {
- while(rest>=18) {
- adx_decode(samples,buf,c->prev);
- rest-=18;
- buf+=18;
- samples+=32;
+ if (avctx->channels == 1) {
+ while (rest >= 18) {
+ adx_decode(samples, buf, c->prev);
+ rest -= 18;
+ buf += 18;
+ samples += 32;
}
} else {
- while(rest>=18*2) {
- adx_decode_stereo(samples,buf,c->prev);
- rest-=18*2;
- buf+=18*2;
- samples+=32*2;
+ while (rest >= 18 * 2) {
+ adx_decode_stereo(samples, buf, c->prev);
+ rest -= 18 * 2;
+ buf += 18 * 2;
+ samples += 32 * 2;
}
}
c->in_temp = rest;
if (rest) {
- memcpy(c->dec_temp,buf,rest);
- buf+=rest;
+ memcpy(c->dec_temp, buf, rest);
+ buf += rest;
}
*data_size = (uint8_t*)samples - (uint8_t*)data;
- return buf-buf0;
+ return buf - buf0;
}
AVCodec ff_adpcm_adx_decoder = {
@@ -170,6 +183,5 @@ AVCodec ff_adpcm_adx_decoder = {
.priv_data_size = sizeof(ADXContext),
.init = adx_decode_init,
.decode = adx_decode_frame,
- .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
+ .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
};
-
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