[FFmpeg-cvslog] r12195 - in trunk/libavcodec: png.h pngenc.c
lorenm
subversion
Mon Feb 25 11:34:24 CET 2008
Author: lorenm
Date: Mon Feb 25 11:34:23 2008
New Revision: 12195
Log:
png filters
Modified:
trunk/libavcodec/png.h
trunk/libavcodec/pngenc.c
Modified: trunk/libavcodec/png.h
==============================================================================
--- trunk/libavcodec/png.h (original)
+++ trunk/libavcodec/png.h Mon Feb 25 11:34:23 2008
@@ -39,6 +39,7 @@
#define PNG_FILTER_VALUE_UP 2
#define PNG_FILTER_VALUE_AVG 3
#define PNG_FILTER_VALUE_PAETH 4
+#define PNG_FILTER_VALUE_MIXED 5
#define PNG_IHDR 0x0001
#define PNG_IDAT 0x0002
Modified: trunk/libavcodec/pngenc.c
==============================================================================
--- trunk/libavcodec/pngenc.c (original)
+++ trunk/libavcodec/pngenc.c Mon Feb 25 11:34:23 2008
@@ -21,10 +21,10 @@
#include "avcodec.h"
#include "bytestream.h"
#include "png.h"
+#include <dsputil.h>
/* TODO:
* - add 2, 4 and 16 bit depth support
- * - use filters when generating a png (better compression)
*/
#include <zlib.h>
@@ -34,11 +34,15 @@
#define IOBUF_SIZE 4096
typedef struct PNGEncContext {
+ DSPContext dsp;
+
uint8_t *bytestream;
uint8_t *bytestream_start;
uint8_t *bytestream_end;
AVFrame picture;
+ int filter_type;
+
z_stream zstream;
uint8_t buf[IOBUF_SIZE];
} PNGEncContext;
@@ -81,6 +85,93 @@ static void png_get_interlaced_row(uint8
}
}
+static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
+{
+ int i;
+ for(i = 0; i < w; i++) {
+ int a, b, c, p, pa, pb, pc;
+
+ a = src[i - bpp];
+ b = top[i];
+ c = top[i - bpp];
+
+ p = b - c;
+ pc = a - c;
+
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+
+ if (pa <= pb && pa <= pc)
+ p = a;
+ else if (pb <= pc)
+ p = b;
+ else
+ p = c;
+ dst[i] = src[i] - p;
+ }
+}
+
+static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
+ uint8_t *src, uint8_t *top, int size, int bpp)
+{
+ int i;
+
+ switch(filter_type) {
+ case PNG_FILTER_VALUE_NONE:
+ memcpy(dst, src, size);
+ break;
+ case PNG_FILTER_VALUE_SUB:
+ dsp->diff_bytes(dst, src, src-bpp, size);
+ memcpy(dst, src, bpp);
+ break;
+ case PNG_FILTER_VALUE_UP:
+ dsp->diff_bytes(dst, src, top, size);
+ break;
+ case PNG_FILTER_VALUE_AVG:
+ for(i = 0; i < bpp; i++)
+ dst[i] = src[i] - (top[i] >> 1);
+ for(; i < size; i++)
+ dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);
+ break;
+ case PNG_FILTER_VALUE_PAETH:
+ for(i = 0; i < bpp; i++)
+ dst[i] = src[i] - top[i];
+ sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp);
+ break;
+ }
+}
+
+static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
+ uint8_t *src, uint8_t *top, int size, int bpp)
+{
+ int pred = s->filter_type;
+ assert(bpp || !pred);
+ if(!top && pred)
+ pred = PNG_FILTER_VALUE_SUB;
+ if(pred == PNG_FILTER_VALUE_MIXED) {
+ int i;
+ int cost, bcost = INT_MAX;
+ uint8_t *buf1 = dst, *buf2 = dst + size + 16;
+ for(pred=0; pred<5; pred++) {
+ png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp);
+ buf1[0] = pred;
+ cost = 0;
+ for(i=0; i<=size; i++)
+ cost += abs(0x80 - (buf1[i] ^ 0x80));
+ if(cost < bcost) {
+ bcost = cost;
+ FFSWAP(uint8_t*, buf1, buf2);
+ }
+ }
+ return buf2;
+ } else {
+ png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);
+ dst[0] = pred;
+ return dst;
+ }
+}
+
static void convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width)
{
uint8_t *d;
@@ -145,9 +236,11 @@ static int encode_frame(AVCodecContext *
int bit_depth, color_type, y, len, row_size, ret, is_progressive;
int bits_per_pixel, pass_row_size;
int compression_level;
- uint8_t *ptr;
- uint8_t *crow_buf = NULL;
- uint8_t *tmp_buf = NULL;
+ uint8_t *ptr, *top;
+ uint8_t *crow_base = NULL, *crow_buf, *crow;
+ uint8_t *progressive_buf = NULL;
+ uint8_t *rgba_buf = NULL;
+ uint8_t *top_buf = NULL;
*p = *pict;
p->pict_type= FF_I_TYPE;
@@ -195,12 +288,23 @@ static int encode_frame(AVCodecContext *
Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
if (ret != Z_OK)
return -1;
- crow_buf = av_malloc(row_size + 1);
- if (!crow_buf)
+ crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
+ if (!crow_base)
goto fail;
+ crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it
if (is_progressive) {
- tmp_buf = av_malloc(row_size + 1);
- if (!tmp_buf)
+ progressive_buf = av_malloc(row_size + 1);
+ if (!progressive_buf)
+ goto fail;
+ }
+ if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
+ rgba_buf = av_malloc(row_size + 1);
+ if (!rgba_buf)
+ goto fail;
+ }
+ if (is_progressive || color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
+ top_buf = av_malloc(row_size + 1);
+ if (!top_buf)
goto fail;
}
@@ -247,7 +351,6 @@ static int encode_frame(AVCodecContext *
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (is_progressive) {
- uint8_t *ptr1;
int pass;
for(pass = 0; pass < NB_PASSES; pass++) {
@@ -255,33 +358,37 @@ static int encode_frame(AVCodecContext *
output */
pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
if (pass_row_size > 0) {
+ top = NULL;
for(y = 0; y < avctx->height; y++) {
if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
ptr = p->data[0] + y * p->linesize[0];
+ FFSWAP(uint8_t*, progressive_buf, top_buf);
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
- convert_from_rgb32(tmp_buf, ptr, avctx->width);
- ptr1 = tmp_buf;
- } else {
- ptr1 = ptr;
+ convert_from_rgb32(rgba_buf, ptr, avctx->width);
+ ptr = rgba_buf;
}
- png_get_interlaced_row(crow_buf + 1, pass_row_size,
+ png_get_interlaced_row(progressive_buf, pass_row_size,
bits_per_pixel, pass,
- ptr1, avctx->width);
- crow_buf[0] = PNG_FILTER_VALUE_NONE;
- png_write_row(s, crow_buf, pass_row_size + 1);
+ ptr, avctx->width);
+ crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3);
+ png_write_row(s, crow, pass_row_size + 1);
+ top = progressive_buf;
}
}
}
}
} else {
+ top = NULL;
for(y = 0; y < avctx->height; y++) {
ptr = p->data[0] + y * p->linesize[0];
- if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- convert_from_rgb32(crow_buf + 1, ptr, avctx->width);
- else
- memcpy(crow_buf + 1, ptr, row_size);
- crow_buf[0] = PNG_FILTER_VALUE_NONE;
- png_write_row(s, crow_buf, row_size + 1);
+ if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
+ FFSWAP(uint8_t*, rgba_buf, top_buf);
+ convert_from_rgb32(rgba_buf, ptr, avctx->width);
+ ptr = rgba_buf;
+ }
+ crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);
+ png_write_row(s, crow, row_size + 1);
+ top = ptr;
}
}
/* compress last bytes */
@@ -304,8 +411,10 @@ static int encode_frame(AVCodecContext *
ret = s->bytestream - s->bytestream_start;
the_end:
- av_free(crow_buf);
- av_free(tmp_buf);
+ av_free(crow_base);
+ av_free(progressive_buf);
+ av_free(rgba_buf);
+ av_free(top_buf);
deflateEnd(&s->zstream);
return ret;
fail:
@@ -318,6 +427,11 @@ static int png_enc_init(AVCodecContext *
avcodec_get_frame_defaults((AVFrame*)&s->picture);
avctx->coded_frame= (AVFrame*)&s->picture;
+ dsputil_init(&s->dsp, avctx);
+
+ s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);
+ if(avctx->pix_fmt == PIX_FMT_MONOBLACK)
+ s->filter_type = PNG_FILTER_VALUE_NONE;
return 0;
}
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