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ffmpeg/libavcodec/pngenc.c

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/*
* PNG image format
* Copyright (c) 2003 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
#include "internal.h"
#include "bytestream.h"
#include "dsputil.h"
#include "png.h"
#include "libavutil/avassert.h"
#include "libavutil/opt.h"
#include <zlib.h>
#define IOBUF_SIZE 4096
typedef struct PNGEncContext {
AVClass *class;
DSPContext dsp;
uint8_t *bytestream;
uint8_t *bytestream_start;
uint8_t *bytestream_end;
int filter_type;
z_stream zstream;
uint8_t buf[IOBUF_SIZE];
int dpi; ///< Physical pixel density, in dots per inch, if set
int dpm; ///< Physical pixel density, in dots per meter, if set
} PNGEncContext;
static void png_get_interlaced_row(uint8_t *dst, int row_size,
int bits_per_pixel, int pass,
const uint8_t *src, int width)
{
int x, mask, dst_x, j, b, bpp;
uint8_t *d;
const uint8_t *s;
static const int masks[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
mask = masks[pass];
switch(bits_per_pixel) {
case 1:
memset(dst, 0, row_size);
dst_x = 0;
for(x = 0; x < width; x++) {
j = (x & 7);
if ((mask << j) & 0x80) {
b = (src[x >> 3] >> (7 - j)) & 1;
dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
dst_x++;
}
}
break;
default:
bpp = bits_per_pixel >> 3;
d = dst;
s = src;
for(x = 0; x < width; x++) {
j = x & 7;
if ((mask << j) & 0x80) {
memcpy(d, s, bpp);
d += bpp;
}
s += bpp;
}
break;
}
}
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 sub_left_prediction(DSPContext *dsp, uint8_t *dst, const uint8_t *src, int bpp, int size)
{
const uint8_t *src1 = src + bpp;
const uint8_t *src2 = src;
int x, unaligned_w;
memcpy(dst, src, bpp);
dst += bpp;
size -= bpp;
unaligned_w = FFMIN(32 - bpp, size);
for (x = 0; x < unaligned_w; x++)
*dst++ = *src1++ - *src2++;
size -= unaligned_w;
dsp->diff_bytes(dst, src1, src2, size);
}
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:
sub_left_prediction(dsp, dst, src, bpp, size);
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;
av_assert0(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((int8_t)buf1[i]);
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 png_write_chunk(uint8_t **f, uint32_t tag,
const uint8_t *buf, int length)
{
uint32_t crc;
uint8_t tagbuf[4];
bytestream_put_be32(f, length);
crc = crc32(0, Z_NULL, 0);
AV_WL32(tagbuf, tag);
crc = crc32(crc, tagbuf, 4);
bytestream_put_be32(f, av_bswap32(tag));
if (length > 0) {
crc = crc32(crc, buf, length);
memcpy(*f, buf, length);
*f += length;
}
bytestream_put_be32(f, crc);
}
/* XXX: do filtering */
static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
{
int ret;
s->zstream.avail_in = size;
s->zstream.next_in = (uint8_t *)data;
while (s->zstream.avail_in > 0) {
ret = deflate(&s->zstream, Z_NO_FLUSH);
if (ret != Z_OK)
return -1;
if (s->zstream.avail_out == 0) {
if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
}
}
return 0;
}
static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *pict, int *got_packet)
{
PNGEncContext *s = avctx->priv_data;
const AVFrame * const p = pict;
int bit_depth, color_type, y, len, row_size, ret, is_progressive;
int bits_per_pixel, pass_row_size, enc_row_size;
int64_t max_packet_size;
int compression_level;
uint8_t *ptr, *top;
uint8_t *crow_base = NULL, *crow_buf, *crow;
uint8_t *progressive_buf = NULL;
uint8_t *top_buf = NULL;
is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
switch(avctx->pix_fmt) {
case AV_PIX_FMT_RGBA64BE:
bit_depth = 16;
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case AV_PIX_FMT_RGB48BE:
bit_depth = 16;
color_type = PNG_COLOR_TYPE_RGB;
break;
case AV_PIX_FMT_RGBA:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case AV_PIX_FMT_RGB24:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB;
break;
case AV_PIX_FMT_GRAY16BE:
bit_depth = 16;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_GRAY8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_GRAY8A:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
break;
case AV_PIX_FMT_MONOBLACK:
bit_depth = 1;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_PAL8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_PALETTE;
break;
default:
return -1;
}
bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
row_size = (avctx->width * bits_per_pixel + 7) >> 3;
s->zstream.zalloc = ff_png_zalloc;
s->zstream.zfree = ff_png_zfree;
s->zstream.opaque = NULL;
compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
Z_DEFAULT_COMPRESSION :
av_clip(avctx->compression_level, 0, 9);
ret = deflateInit2(&s->zstream, compression_level,
Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
if (ret != Z_OK)
return -1;
enc_row_size = deflateBound(&s->zstream, row_size);
max_packet_size = avctx->height * (int64_t)(enc_row_size +
((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)
+ FF_MIN_BUFFER_SIZE;
if (max_packet_size > INT_MAX)
return AVERROR(ENOMEM);
if ((ret = ff_alloc_packet2(avctx, pkt, max_packet_size)) < 0)
return ret;
s->bytestream_start =
s->bytestream = pkt->data;
s->bytestream_end = pkt->data + pkt->size;
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) {
progressive_buf = av_malloc(row_size + 1);
if (!progressive_buf)
goto fail;
}
if (is_progressive) {
top_buf = av_malloc(row_size + 1);
if (!top_buf)
goto fail;
}
/* write png header */
AV_WB64(s->bytestream, PNGSIG);
s->bytestream += 8;
AV_WB32(s->buf, avctx->width);
AV_WB32(s->buf + 4, avctx->height);
s->buf[8] = bit_depth;
s->buf[9] = color_type;
s->buf[10] = 0; /* compression type */
s->buf[11] = 0; /* filter type */
s->buf[12] = is_progressive; /* interlace type */
png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
if (s->dpm) {
AV_WB32(s->buf, s->dpm);
AV_WB32(s->buf + 4, s->dpm);
s->buf[8] = 1; /* unit specifier is meter */
} else {
AV_WB32(s->buf, avctx->sample_aspect_ratio.num);
AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);
s->buf[8] = 0; /* unit specifier is unknown */
}
png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);
/* put the palette if needed */
if (color_type == PNG_COLOR_TYPE_PALETTE) {
int has_alpha, alpha, i;
unsigned int v;
uint32_t *palette;
uint8_t *alpha_ptr;
palette = (uint32_t *)p->data[1];
ptr = s->buf;
alpha_ptr = s->buf + 256 * 3;
has_alpha = 0;
for(i = 0; i < 256; i++) {
v = palette[i];
alpha = v >> 24;
if (alpha != 0xff)
has_alpha = 1;
*alpha_ptr++ = alpha;
bytestream_put_be24(&ptr, v);
}
png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
if (has_alpha) {
png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
}
}
/* now put each row */
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (is_progressive) {
int pass;
for(pass = 0; pass < NB_PASSES; pass++) {
/* NOTE: a pass is completely omitted if no pixels would be
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);
png_get_interlaced_row(progressive_buf, pass_row_size,
bits_per_pixel, pass,
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];
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 */
for(;;) {
ret = deflate(&s->zstream, Z_FINISH);
if (ret == Z_OK || ret == Z_STREAM_END) {
len = IOBUF_SIZE - s->zstream.avail_out;
if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
}
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (ret == Z_STREAM_END)
break;
} else {
goto fail;
}
}
png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
pkt->size = s->bytestream - s->bytestream_start;
pkt->flags |= AV_PKT_FLAG_KEY;
*got_packet = 1;
ret = 0;
the_end:
av_free(crow_base);
av_free(progressive_buf);
av_free(top_buf);
deflateEnd(&s->zstream);
return ret;
fail:
ret = -1;
goto the_end;
}
static av_cold int png_enc_init(AVCodecContext *avctx){
PNGEncContext *s = avctx->priv_data;
switch(avctx->pix_fmt) {
case AV_PIX_FMT_RGBA:
avctx->bits_per_coded_sample = 32;
break;
case AV_PIX_FMT_RGB24:
avctx->bits_per_coded_sample = 24;
break;
case AV_PIX_FMT_GRAY8:
avctx->bits_per_coded_sample = 0x28;
break;
case AV_PIX_FMT_MONOBLACK:
avctx->bits_per_coded_sample = 1;
break;
case AV_PIX_FMT_PAL8:
avctx->bits_per_coded_sample = 8;
}
avctx->coded_frame = av_frame_alloc();
if (!avctx->coded_frame)
return AVERROR(ENOMEM);
avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
avctx->coded_frame->key_frame = 1;
ff_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 == AV_PIX_FMT_MONOBLACK)
s->filter_type = PNG_FILTER_VALUE_NONE;
if (s->dpi && s->dpm) {
av_log(avctx, AV_LOG_ERROR, "Only one of 'dpi' or 'dpm' options should be set\n");
return AVERROR(EINVAL);
} else if (s->dpi) {
s->dpm = s->dpi * 10000 / 254;
}
return 0;
}
static av_cold int png_enc_close(AVCodecContext *avctx)
{
av_frame_free(&avctx->coded_frame);
return 0;
}
#define OFFSET(x) offsetof(PNGEncContext, x)
#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"dpi", "Set image resolution (in dots per inch)", OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
{"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},
{ NULL }
};
static const AVClass pngenc_class = {
.class_name = "PNG encoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_png_encoder = {
.name = "png",
.long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_PNG,
.priv_data_size = sizeof(PNGEncContext),
.init = png_enc_init,
.close = png_enc_close,
.encode2 = encode_frame,
.capabilities = CODEC_CAP_FRAME_THREADS | CODEC_CAP_INTRA_ONLY,
.pix_fmts = (const enum AVPixelFormat[]){
AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
AV_PIX_FMT_PAL8,
AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
AV_PIX_FMT_GRAY16BE,
AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
},
.priv_class = &pngenc_class,
};
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