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authorMalcolm Bechard <malcolm.bechard@gmail.com>2013-02-20 15:50:34 -0500
committerMichael Niedermayer <michaelni@gmx.at>2013-02-22 21:41:54 +0100
commit239b88c284af3025513e5cac6e318d1f9a9cdd71 (patch)
tree91e13e278a85516c871308df03153bf201b891a0 /libavcodec/qtrleenc.c
parent2c21d34ea44d38835f85b90de3cbbf54abb894be (diff)
downloadffmpeg-239b88c284af3025513e5cac6e318d1f9a9cdd71.tar.gz
Improve QTRLE encoding performance, no change to output file size/content.
Avoid searching for the lowest bulk cost for each pixel that isn't a repeat/skip. Instead store the lowest cost as we go along each pixel, and use it as needed. Signed-off-by: Malcolm Bechard <malcolm.bechard@gmail.com> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavcodec/qtrleenc.c')
-rw-r--r--libavcodec/qtrleenc.c82
1 files changed, 61 insertions, 21 deletions
diff --git a/libavcodec/qtrleenc.c b/libavcodec/qtrleenc.c
index e151c9e1fa..a25c45d6db 100644
--- a/libavcodec/qtrleenc.c
+++ b/libavcodec/qtrleenc.c
@@ -121,8 +121,6 @@ static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, ui
int i;
signed char rlecode;
- /* We will use it to compute the best bulk copy sequence */
- unsigned int av_uninit(bulkcount);
/* This will be the number of pixels equal to the preivous frame one's
* starting from the ith pixel */
unsigned int skipcount;
@@ -131,12 +129,14 @@ static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, ui
unsigned int av_uninit(repeatcount);
/* The cost of the three different possibilities */
- int total_bulk_cost;
int total_skip_cost;
int total_repeat_cost;
- int temp_cost;
- int j;
+ int base_bulk_cost;
+ int lowest_bulk_cost;
+ int lowest_bulk_cost_index;
+ int sec_lowest_bulk_cost;
+ int sec_lowest_bulk_cost_index;
uint8_t *this_line = p-> data[0] + line*p-> linesize[0] +
(width - 1)*s->pixel_size;
@@ -146,8 +146,57 @@ static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, ui
s->length_table[width] = 0;
skipcount = 0;
+ /* Initial values */
+ lowest_bulk_cost = INT_MAX / 2;
+ lowest_bulk_cost_index = width;
+ sec_lowest_bulk_cost = INT_MAX / 2;
+ sec_lowest_bulk_cost_index = width;
+
+ base_bulk_cost = 1 + s->pixel_size;
+
for (i = width - 1; i >= 0; i--) {
+ int prev_bulk_cost;
+
+ /* If our lowest bulk cost index is too far away, replace it
+ * with the next lowest bulk cost */
+ if (FFMIN(width, i + MAX_RLE_BULK) < lowest_bulk_cost_index) {
+ lowest_bulk_cost = sec_lowest_bulk_cost;
+ lowest_bulk_cost_index = sec_lowest_bulk_cost_index;
+
+ sec_lowest_bulk_cost = INT_MAX / 2;
+ sec_lowest_bulk_cost_index = width;
+ }
+
+ /* Deal with the first pixel's bulk cost */
+ if (!i) {
+ base_bulk_cost++;
+ lowest_bulk_cost++;
+ sec_lowest_bulk_cost++;
+ }
+
+ /* Look at the bulk cost of the previous loop and see if it is
+ * a new lower bulk cost */
+ prev_bulk_cost = s->length_table[i + 1] + base_bulk_cost;
+ if (prev_bulk_cost <= sec_lowest_bulk_cost) {
+ /* If it's lower than the 2nd lowest, then it may be lower
+ * than the lowest */
+ if (prev_bulk_cost <= lowest_bulk_cost) {
+
+ /* If we have found a new lowest bulk cost,
+ * then the 2nd lowest bulk cost is now farther than the
+ * lowest bulk cost, and will never be used */
+ sec_lowest_bulk_cost = INT_MAX / 2;
+
+ lowest_bulk_cost = prev_bulk_cost;
+ lowest_bulk_cost_index = i + 1;
+ } else {
+ /* Then it must be the 2nd lowest bulk cost */
+ sec_lowest_bulk_cost = prev_bulk_cost;
+ sec_lowest_bulk_cost_index = i + 1;
+ }
+ }
+
if (!s->frame.key_frame && !memcmp(this_line, prev_line, s->pixel_size))
skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
else
@@ -183,26 +232,17 @@ static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, ui
}
else {
/* We cannot do neither skip nor repeat
- * thus we search for the best bulk copy to do */
+ * thus we use the best bulk copy */
- int limit = FFMIN(width - i, MAX_RLE_BULK);
+ s->length_table[i] = lowest_bulk_cost;
+ s->rlecode_table[i] = lowest_bulk_cost_index - i;
- temp_cost = 1 + s->pixel_size + !i;
- total_bulk_cost = INT_MAX;
-
- for (j = 1; j <= limit; j++) {
- if (s->length_table[i + j] + temp_cost < total_bulk_cost) {
- /* We have found a better bulk copy ... */
- total_bulk_cost = s->length_table[i + j] + temp_cost;
- bulkcount = j;
- }
- temp_cost += s->pixel_size;
- }
-
- s->length_table[i] = total_bulk_cost;
- s->rlecode_table[i] = bulkcount;
}
+ /* These bulk costs increase every iteration */
+ lowest_bulk_cost += s->pixel_size;
+ sec_lowest_bulk_cost += s->pixel_size;
+
this_line -= s->pixel_size;
prev_line -= s->pixel_size;
}