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aacenc: Factorize some scalefactor utilities.

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Originally committed as revision 24472 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Alex Converse 2010-07-23 22:37:42 +00:00
parent 3611e7a309
commit 04d72abf17
1 changed files with 14 additions and 4 deletions
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18
libavcodec/aaccoder.c
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@ -515,6 +515,16 @@ static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
}
}
/** Return the minimum scalefactor where the quantized coef does not clip. */
static av_always_inline uint8_t coef2minsf(float coef) {
return av_clip_uint8(log2(coef)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
}
/** Return the maximum scalefactor where the quantized coef is not zero. */
static av_always_inline uint8_t coef2maxsf(float coef) {
return av_clip_uint8(log2(coef)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
}
typedef struct TrellisPath {
float cost;
int prev;
@ -554,9 +564,9 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
}
//minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
q0 = av_clip_uint8(log2(q0f)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
q0 = coef2minsf(q0f);
//maximum scalefactor index is when maximum coefficient after quantizing is still not zero
q1 = av_clip_uint8(log2(q1f)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
q1 = coef2maxsf(q1f);
//av_log(NULL, AV_LOG_ERROR, "q0 %d, q1 %d\n", q0, q1);
if (q1 - q0 > 60) {
int q0low = q0;
@ -618,9 +628,9 @@ static void search_for_quantizers_anmr(AVCodecContext *avctx, AACEncContext *s,
float minrd = INFINITY;
float maxval;
//minimum scalefactor index is when minimum nonzero coefficient after quantizing is not clipped
minscale = av_clip_uint8(log2(qmin)*4 - 69 + SCALE_ONE_POS - SCALE_DIV_512);
minscale = coef2minsf(qmin);
//maximum scalefactor index is when maximum coefficient after quantizing is still not zero
maxscale = av_clip_uint8(log2(qmax)*4 + 6 + SCALE_ONE_POS - SCALE_DIV_512);
maxscale = coef2maxsf(qmax);
minscale = av_clip(minscale - q0, 0, TRELLIS_STATES - 1);
maxscale = av_clip(maxscale - q0, 0, TRELLIS_STATES);
maxval = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], s->scoefs+start);