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Code Issues Releases Activity

8svx: output 8-bit samples instead of 16-bit.

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Based on a patch by Stefano Sabatini.
git.videolan.org/ffmpeg.git
commit e280a4da2ae6fd44f0079358ecc5aa08e388a5ed
This commit is contained in:
Justin Ruggles 2011-09-06 18:40:06 -04:00
parent ac68607bfe
commit e371878416
1 changed files with 18 additions and 19 deletions
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37
libavcodec/8svx.c
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@ -32,14 +32,14 @@
/** decoder context */
typedef struct EightSvxContext {
int16_t fib_acc;
const int16_t *table;
uint8_t fib_acc;
const int8_t *table;
} EightSvxContext;
static const int16_t fibonacci[16] = { -34<<8, -21<<8, -13<<8, -8<<8, -5<<8, -3<<8, -2<<8, -1<<8,
0, 1<<8, 2<<8, 3<<8, 5<<8, 8<<8, 13<<8, 21<<8 };
static const int16_t exponential[16] = { -128<<8, -64<<8, -32<<8, -16<<8, -8<<8, -4<<8, -2<<8, -1<<8,
0, 1<<8, 2<<8, 4<<8, 8<<8, 16<<8, 32<<8, 64<<8 };
static const int8_t fibonacci[16] = { -34, -21, -13, -8, -5, -3, -2, -1,
0, 1, 2, 3, 5, 8, 13, 21 };
static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1,
0, 1, 2, 4, 8, 16, 32, 64 };
/**
* Delta decode the compressed values in src, and put the resulting
@ -47,16 +47,16 @@ static const int16_t exponential[16] = { -128<<8, -64<<8, -32<<8, -16<<8, -8<<8,
*
* @param[in,out] state starting value. it is saved for use in the next call.
*/
static void delta_decode(int16_t *dst, const uint8_t *src, int src_size,
int16_t *state, const int16_t *table)
static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
uint8_t *state, const int8_t *table)
{
int val = *state;
uint8_t val = *state;
while (src_size--) {
uint8_t d = *src++;
val = av_clip_int16(val + table[d & 0xF]);
val = av_clip_uint8(val + table[d & 0xF]);
*dst++ = val;
val = av_clip_int16(val + table[d >> 4]);
val = av_clip_uint8(val + table[d >> 4]);
*dst++ = val;
}
@ -70,23 +70,22 @@ static int eightsvx_decode_frame(AVCodecContext *avctx, void *data, int *data_si
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
EightSvxContext *esc = avctx->priv_data;
int16_t *out_data = data;
uint8_t *out_data = data;
int consumed = buf_size;
const uint8_t *buf_end = buf + buf_size;
if((*data_size >> 2) < buf_size)
return -1;
if(avctx->frame_number == 0) {
esc->fib_acc = buf[1] << 8;
esc->fib_acc = (int8_t)buf[1] + 128;
buf_size -= 2;
buf += 2;
}
*data_size = buf_size << 2;
if (*data_size < buf_size * 2)
return AVERROR(EINVAL);
delta_decode(out_data, buf, buf_size, &esc->fib_acc, esc->table);
*data_size = buf_size * 2;
return consumed;
}
@ -105,7 +104,7 @@ static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
default:
return -1;
}
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
avctx->sample_fmt = AV_SAMPLE_FMT_U8;
return 0;
}