[FFmpeg-cvslog] avcodec/flacenc: Support calculating rice parameters exactly
Michael Niedermayer
git at videolan.org
Tue May 19 14:05:56 CEST 2015
ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Tue May 19 13:26:55 2015 +0200| [80f9d6e0ab242d0549ee47ffbfe8e58bd78cad12] | committer: Michael Niedermayer
avcodec/flacenc: Support calculating rice parameters exactly
Some files benefit by about 0.3% from this, and speedwise its ok
other files do not benefit and encode to the same size
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=80f9d6e0ab242d0549ee47ffbfe8e58bd78cad12
---
libavcodec/flacenc.c | 89 +++++++++++++++++++++++++++++++++++---------------
1 file changed, 62 insertions(+), 27 deletions(-)
diff --git a/libavcodec/flacenc.c b/libavcodec/flacenc.c
index e7f074b..3512e06 100644
--- a/libavcodec/flacenc.c
+++ b/libavcodec/flacenc.c
@@ -62,6 +62,7 @@ typedef struct CompressionOptions {
int min_partition_order;
int max_partition_order;
int ch_mode;
+ int exact_rice_parameters;
} CompressionOptions;
typedef struct RiceContext {
@@ -586,24 +587,44 @@ static int find_optimal_param(uint64_t sum, int n, int max_param)
return FFMIN(k, max_param);
}
+static int find_optimal_param_exact(uint64_t sums[32][MAX_PARTITIONS], int i, int max_param)
+{
+ int bestk = 0;
+ int64_t bestbits = INT64_MAX;
+ int k;
+
+ for (k = 0; k <= max_param; k++) {
+ int64_t bits = sums[k][i];
+ if (bits < bestbits) {
+ bestbits = bits;
+ bestk = k;
+ }
+ }
+
+ return bestk;
+}
static uint64_t calc_optimal_rice_params(RiceContext *rc, int porder,
- uint64_t *sums, int n, int pred_order)
+ uint64_t sums[32][MAX_PARTITIONS],
+ int n, int pred_order, int max_param, int exact)
{
int i;
- int k, cnt, part, max_param;
+ int k, cnt, part;
uint64_t all_bits;
- max_param = (1 << rc->coding_mode) - 2;
-
part = (1 << porder);
all_bits = 4 * part;
cnt = (n >> porder) - pred_order;
for (i = 0; i < part; i++) {
- k = find_optimal_param(sums[i], cnt, max_param);
+ if (exact) {
+ k = find_optimal_param_exact(sums, i, max_param);
+ all_bits += sums[k][i];
+ } else {
+ k = find_optimal_param(sums[0][i], cnt, max_param);
+ all_bits += rice_encode_count(sums[0][i], cnt, k);
+ }
rc->params[i] = k;
- all_bits += rice_encode_count(sums[i], cnt, k);
cnt = n >> porder;
}
@@ -613,42 +634,55 @@ static uint64_t calc_optimal_rice_params(RiceContext *rc, int porder,
}
-static void calc_sum_top(int pmax, uint32_t *data, int n, int pred_order,
- uint64_t sums[MAX_PARTITIONS])
+static void calc_sum_top(int pmax, int kmax, uint32_t *data, int n, int pred_order,
+ uint64_t sums[32][MAX_PARTITIONS])
{
- int i;
+ int i, k;
int parts;
uint32_t *res, *res_end;
/* sums for highest level */
parts = (1 << pmax);
- res = &data[pred_order];
- res_end = &data[n >> pmax];
- for (i = 0; i < parts; i++) {
- uint64_t sum = 0;
- while (res < res_end)
- sum += *(res++);
- sums[i] = sum;
- res_end += n >> pmax;
+
+ for (k = 0; k <= kmax; k++) {
+ res = &data[pred_order];
+ res_end = &data[n >> pmax];
+ for (i = 0; i < parts; i++) {
+ if (kmax) {
+ uint64_t sum = (1LL + k) * (res_end - res);
+ while (res < res_end)
+ sum += *(res++) >> k;
+ sums[k][i] = sum;
+ } else {
+ uint64_t sum = 0;
+ while (res < res_end)
+ sum += *(res++);
+ sums[k][i] = sum;
+ }
+ res_end += n >> pmax;
+ }
}
}
-static void calc_sum_next(int level, uint64_t sums[MAX_PARTITIONS])
+static void calc_sum_next(int level, uint64_t sums[32][MAX_PARTITIONS], int kmax)
{
- int i;
+ int i, k;
int parts = (1 << level);
- for (i = 0; i < parts; i++)
- sums[i] = sums[2*i] + sums[2*i+1];
+ for (i = 0; i < parts; i++) {
+ for (k=0; k<=kmax; k++)
+ sums[k][i] = sums[k][2*i] + sums[k][2*i+1];
+ }
}
static uint64_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
- int32_t *data, int n, int pred_order)
+ int32_t *data, int n, int pred_order, int exact)
{
int i;
uint64_t bits[MAX_PARTITION_ORDER+1];
int opt_porder;
RiceContext tmp_rc;
- uint64_t sums[MAX_PARTITIONS];
+ uint64_t sums[32][MAX_PARTITIONS];
+ int kmax = (1 << rc->coding_mode) - 2;
av_assert1(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
av_assert1(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
@@ -659,12 +693,12 @@ static uint64_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
for (i = 0; i < n; i++)
rc->udata[i] = (2 * data[i]) ^ (data[i] >> 31);
- calc_sum_top(pmax, rc->udata, n, pred_order, sums);
+ calc_sum_top(pmax, exact ? kmax : 0, rc->udata, n, pred_order, sums);
opt_porder = pmin;
bits[pmin] = UINT32_MAX;
for (i = pmax; ; ) {
- bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums, n, pred_order);
+ bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums, n, pred_order, kmax, exact);
if (bits[i] < bits[opt_porder]) {
opt_porder = i;
rc->coding_mode = tmp_rc.coding_mode;
@@ -673,7 +707,7 @@ static uint64_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
}
if (i == pmin)
break;
- calc_sum_next(--i, sums);
+ calc_sum_next(--i, sums, exact ? kmax : 0);
}
return bits[opt_porder];
@@ -701,7 +735,7 @@ static uint64_t find_subframe_rice_params(FlacEncodeContext *s,
if (sub->type == FLAC_SUBFRAME_LPC)
bits += 4 + 5 + pred_order * s->options.lpc_coeff_precision;
bits += calc_rice_params(&sub->rc, pmin, pmax, sub->residual,
- s->frame.blocksize, pred_order);
+ s->frame.blocksize, pred_order, s->options.exact_rice_parameters);
return bits;
}
@@ -1375,6 +1409,7 @@ static const AVOption options[] = {
{ "left_side", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_LEFT_SIDE }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
{ "right_side", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_RIGHT_SIDE }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
{ "mid_side", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_MID_SIDE }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
+{ "exact_rice_parameters", "Calculate rice parameters exactly", offsetof(FlacEncodeContext, options.exact_rice_parameters), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS },
{ NULL },
};
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