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FFmpeg/libavcodec/pngenc.c
Leo Izen c125860892
avcodec/pngenc: write sBIT chunks 
Add support for writing sBIT chunks, which mark the significant
bit depth of the PNG file. This obtains the metadata using the field
bits_per_raw_sample of AVCodecContext.

Signed-off-by: Leo Izen <leo.izen@gmail.com>
2023-04-01 00:37:55 -04:00

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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 "codec_internal.h"
#include "encode.h"
#include "bytestream.h"
#include "lossless_videoencdsp.h"
#include "png.h"
#include "apng.h"
#include "zlib_wrapper.h"
#include "libavutil/avassert.h"
#include "libavutil/crc.h"
#include "libavutil/csp.h"
#include "libavutil/libm.h"
#include "libavutil/opt.h"
#include "libavutil/rational.h"
#include "libavutil/stereo3d.h"
#include <zlib.h>
#define IOBUF_SIZE 4096
typedef struct APNGFctlChunk {
uint32_t sequence_number;
uint32_t width, height;
uint32_t x_offset, y_offset;
uint16_t delay_num, delay_den;
uint8_t dispose_op, blend_op;
} APNGFctlChunk;
typedef struct PNGEncContext {
AVClass *class;
LLVidEncDSPContext llvidencdsp;
uint8_t *bytestream;
uint8_t *bytestream_start;
uint8_t *bytestream_end;
int filter_type;
FFZStream 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
int is_progressive;
int bit_depth;
int color_type;
int bits_per_pixel;
// APNG
uint32_t palette_checksum; // Used to ensure a single unique palette
uint32_t sequence_number;
int extra_data_updated;
uint8_t *extra_data;
int extra_data_size;
AVFrame *prev_frame;
AVFrame *last_frame;
APNGFctlChunk last_frame_fctl;
uint8_t *last_frame_packet;
size_t last_frame_packet_size;
} 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, const uint8_t *src, const 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(PNGEncContext *c, 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;
c->llvidencdsp.diff_bytes(dst, src1, src2, size);
}
static void png_filter_row(PNGEncContext *c, uint8_t *dst, int filter_type,
const uint8_t *src, const 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(c, dst, src, bpp, size);
break;
case PNG_FILTER_VALUE_UP:
c->llvidencdsp.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,
const uint8_t *src, const 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, 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, 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)
{
const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
uint32_t crc = ~0U;
uint8_t tagbuf[4];
bytestream_put_be32(f, length);
AV_WL32(tagbuf, tag);
crc = av_crc(crc_table, crc, tagbuf, 4);
bytestream_put_be32(f, av_bswap32(tag));
if (length > 0) {
crc = av_crc(crc_table, crc, buf, length);
if (*f != buf)
memcpy(*f, buf, length);
*f += length;
}
bytestream_put_be32(f, ~crc);
}
static void png_write_image_data(AVCodecContext *avctx,
const uint8_t *buf, int length)
{
PNGEncContext *s = avctx->priv_data;
const AVCRC *crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
uint32_t crc = ~0U;
if (avctx->codec_id == AV_CODEC_ID_PNG || avctx->frame_num == 0) {
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), buf, length);
return;
}
bytestream_put_be32(&s->bytestream, length + 4);
bytestream_put_be32(&s->bytestream, MKBETAG('f', 'd', 'A', 'T'));
bytestream_put_be32(&s->bytestream, s->sequence_number);
crc = av_crc(crc_table, crc, s->bytestream - 8, 8);
crc = av_crc(crc_table, crc, buf, length);
memcpy(s->bytestream, buf, length);
s->bytestream += length;
bytestream_put_be32(&s->bytestream, ~crc);
++s->sequence_number;
}
/* XXX: do filtering */
static int png_write_row(AVCodecContext *avctx, const uint8_t *data, int size)
{
PNGEncContext *s = avctx->priv_data;
z_stream *const zstream = &s->zstream.zstream;
int ret;
zstream->avail_in = size;
zstream->next_in = data;
while (zstream->avail_in > 0) {
ret = deflate(zstream, Z_NO_FLUSH);
if (ret != Z_OK)
return -1;
if (zstream->avail_out == 0) {
if (s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
png_write_image_data(avctx, s->buf, IOBUF_SIZE);
zstream->avail_out = IOBUF_SIZE;
zstream->next_out = s->buf;
}
}
return 0;
}
#define AV_WB32_PNG(buf, n) AV_WB32(buf, lrint((n) * 100000))
#define AV_WB32_PNG_D(buf, d) AV_WB32_PNG(buf, av_q2d(d))
static int png_get_chrm(enum AVColorPrimaries prim, uint8_t *buf)
{
const AVColorPrimariesDesc *desc = av_csp_primaries_desc_from_id(prim);
if (!desc)
return 0;
AV_WB32_PNG_D(buf, desc->wp.x);
AV_WB32_PNG_D(buf + 4, desc->wp.y);
AV_WB32_PNG_D(buf + 8, desc->prim.r.x);
AV_WB32_PNG_D(buf + 12, desc->prim.r.y);
AV_WB32_PNG_D(buf + 16, desc->prim.g.x);
AV_WB32_PNG_D(buf + 20, desc->prim.g.y);
AV_WB32_PNG_D(buf + 24, desc->prim.b.x);
AV_WB32_PNG_D(buf + 28, desc->prim.b.y);
return 1;
}
static int png_get_gama(enum AVColorTransferCharacteristic trc, uint8_t *buf)
{
double gamma = av_csp_approximate_trc_gamma(trc);
if (gamma <= 1e-6)
return 0;
AV_WB32_PNG(buf, 1.0 / gamma);
return 1;
}
static int png_write_iccp(PNGEncContext *s, const AVFrameSideData *sd)
{
z_stream *const zstream = &s->zstream.zstream;
const AVDictionaryEntry *entry;
const char *name;
uint8_t *start, *buf;
int ret;
if (!sd || !sd->size)
return 0;
zstream->next_in = sd->data;
zstream->avail_in = sd->size;
/* write the chunk contents first */
start = s->bytestream + 8; /* make room for iCCP tag + length */
buf = start;
/* profile description */
entry = av_dict_get(sd->metadata, "name", NULL, 0);
name = (entry && entry->value[0]) ? entry->value : "icc";
for (int i = 0;; i++) {
char c = (i == 79) ? 0 : name[i];
bytestream_put_byte(&buf, c);
if (!c)
break;
}
/* compression method and profile data */
bytestream_put_byte(&buf, 0);
zstream->next_out = buf;
zstream->avail_out = s->bytestream_end - buf;
ret = deflate(zstream, Z_FINISH);
deflateReset(zstream);
if (ret != Z_STREAM_END)
return AVERROR_EXTERNAL;
/* rewind to the start and write the chunk header/crc */
png_write_chunk(&s->bytestream, MKTAG('i', 'C', 'C', 'P'), start,
zstream->next_out - start);
return 0;
}
static int encode_headers(AVCodecContext *avctx, const AVFrame *pict)
{
AVFrameSideData *side_data;
PNGEncContext *s = avctx->priv_data;
int ret;
/* write png header */
AV_WB32(s->buf, avctx->width);
AV_WB32(s->buf + 4, avctx->height);
s->buf[8] = s->bit_depth;
s->buf[9] = s->color_type;
s->buf[10] = 0; /* compression type */
s->buf[11] = 0; /* filter type */
s->buf[12] = s->is_progressive; /* interlace type */
png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
/* write physical information */
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);
/* write stereoscopic information */
side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_STEREO3D);
if (side_data) {
AVStereo3D *stereo3d = (AVStereo3D *)side_data->data;
switch (stereo3d->type) {
case AV_STEREO3D_SIDEBYSIDE:
s->buf[0] = ((stereo3d->flags & AV_STEREO3D_FLAG_INVERT) == 0) ? 1 : 0;
png_write_chunk(&s->bytestream, MKTAG('s', 'T', 'E', 'R'), s->buf, 1);
break;
case AV_STEREO3D_2D:
break;
default:
av_log(avctx, AV_LOG_WARNING, "Only side-by-side stereo3d flag can be defined within sTER chunk\n");
break;
}
}
side_data = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
if ((ret = png_write_iccp(s, side_data)))
return ret;
/* write colorspace information */
if (pict->color_primaries == AVCOL_PRI_BT709 &&
pict->color_trc == AVCOL_TRC_IEC61966_2_1) {
s->buf[0] = 1; /* rendering intent, relative colorimetric by default */
png_write_chunk(&s->bytestream, MKTAG('s', 'R', 'G', 'B'), s->buf, 1);
} else if (pict->color_trc != AVCOL_TRC_UNSPECIFIED && !side_data) {
/*
* Avoid writing cICP if the transfer is unknown. Known primaries
* with unknown transfer can be handled by cHRM.
*
* We also avoid writing cICP if an ICC Profile is present, because
* the standard requires that cICP overrides iCCP.
*
* These values match H.273 so no translation is needed.
*/
s->buf[0] = pict->color_primaries;
s->buf[1] = pict->color_trc;
s->buf[2] = 0; /* colorspace = RGB */
s->buf[3] = pict->color_range == AVCOL_RANGE_MPEG ? 0 : 1;
png_write_chunk(&s->bytestream, MKTAG('c', 'I', 'C', 'P'), s->buf, 4);
}
if (png_get_chrm(pict->color_primaries, s->buf))
png_write_chunk(&s->bytestream, MKTAG('c', 'H', 'R', 'M'), s->buf, 32);
if (png_get_gama(pict->color_trc, s->buf))
png_write_chunk(&s->bytestream, MKTAG('g', 'A', 'M', 'A'), s->buf, 4);
if (avctx->bits_per_raw_sample > 0 && avctx->bits_per_raw_sample < s->bit_depth) {
int len = ff_png_get_nb_channels(s->color_type);
memset(s->buf, avctx->bits_per_raw_sample, len);
png_write_chunk(&s->bytestream, MKTAG('s', 'B', 'I', 'T'), s->buf, len);
}
/* put the palette if needed, must be after colorspace information */
if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
int has_alpha, alpha, i;
unsigned int v;
uint32_t *palette;
uint8_t *ptr, *alpha_ptr;
palette = (uint32_t *)pict->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);
}
}
return 0;
}
static int encode_frame(AVCodecContext *avctx, const AVFrame *pict)
{
PNGEncContext *s = avctx->priv_data;
z_stream *const zstream = &s->zstream.zstream;
const AVFrame *const p = pict;
int y, len, ret;
int row_size, pass_row_size;
uint8_t *crow_buf, *crow;
uint8_t *crow_base = NULL;
uint8_t *progressive_buf = NULL;
uint8_t *top_buf = NULL;
row_size = (pict->width * s->bits_per_pixel + 7) >> 3;
crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
if (!crow_base) {
ret = AVERROR(ENOMEM);
goto the_end;
}
// pixel data should be aligned, but there's a control byte before it
crow_buf = crow_base + 15;
if (s->is_progressive) {
progressive_buf = av_malloc(row_size + 1);
top_buf = av_malloc(row_size + 1);
if (!progressive_buf || !top_buf) {
ret = AVERROR(ENOMEM);
goto the_end;
}
}
/* put each row */
zstream->avail_out = IOBUF_SIZE;
zstream->next_out = s->buf;
if (s->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, s->bits_per_pixel, pict->width);
if (pass_row_size > 0) {
uint8_t *top = NULL;
for (y = 0; y < pict->height; y++)
if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
const uint8_t *ptr = p->data[0] + y * p->linesize[0];
FFSWAP(uint8_t *, progressive_buf, top_buf);
png_get_interlaced_row(progressive_buf, pass_row_size,
s->bits_per_pixel, pass,
ptr, pict->width);
crow = png_choose_filter(s, crow_buf, progressive_buf,
top, pass_row_size, s->bits_per_pixel >> 3);
png_write_row(avctx, crow, pass_row_size + 1);
top = progressive_buf;
}
}
}
} else {
const uint8_t *top = NULL;
for (y = 0; y < pict->height; y++) {
const uint8_t *ptr = p->data[0] + y * p->linesize[0];
crow = png_choose_filter(s, crow_buf, ptr, top,
row_size, s->bits_per_pixel >> 3);
png_write_row(avctx, crow, row_size + 1);
top = ptr;
}
}
/* compress last bytes */
for (;;) {
ret = deflate(zstream, Z_FINISH);
if (ret == Z_OK || ret == Z_STREAM_END) {
len = IOBUF_SIZE - zstream->avail_out;
if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
png_write_image_data(avctx, s->buf, len);
}
zstream->avail_out = IOBUF_SIZE;
zstream->next_out = s->buf;
if (ret == Z_STREAM_END)
break;
} else {
ret = -1;
goto the_end;
}
}
ret = 0;
the_end:
av_freep(&crow_base);
av_freep(&progressive_buf);
av_freep(&top_buf);
deflateReset(zstream);
return ret;
}
static int add_icc_profile_size(AVCodecContext *avctx, const AVFrame *pict,
uint64_t *max_packet_size)
{
PNGEncContext *s = avctx->priv_data;
const AVFrameSideData *sd;
const int hdr_size = 128;
uint64_t new_pkt_size;
uLong bound;
if (!pict)
return 0;
sd = av_frame_get_side_data(pict, AV_FRAME_DATA_ICC_PROFILE);
if (!sd || !sd->size)
return 0;
if (sd->size != (uLong) sd->size)
return AVERROR_INVALIDDATA;
bound = deflateBound(&s->zstream.zstream, sd->size);
if (bound > INT32_MAX - hdr_size)
return AVERROR_INVALIDDATA;
new_pkt_size = *max_packet_size + bound + hdr_size;
if (new_pkt_size < *max_packet_size)
return AVERROR_INVALIDDATA;
*max_packet_size = new_pkt_size;
return 0;
}
static int encode_png(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *pict, int *got_packet)
{
PNGEncContext *s = avctx->priv_data;
int ret;
int enc_row_size;
uint64_t max_packet_size;
enc_row_size = deflateBound(&s->zstream.zstream,
(avctx->width * s->bits_per_pixel + 7) >> 3);
max_packet_size =
AV_INPUT_BUFFER_MIN_SIZE + // headers
avctx->height * (
enc_row_size +
12 * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // IDAT * ceil(enc_row_size / IOBUF_SIZE)
);
if ((ret = add_icc_profile_size(avctx, pict, &max_packet_size)))
return ret;
ret = ff_alloc_packet(avctx, pkt, max_packet_size);
if (ret < 0)
return ret;
s->bytestream_start =
s->bytestream = pkt->data;
s->bytestream_end = pkt->data + pkt->size;
AV_WB64(s->bytestream, PNGSIG);
s->bytestream += 8;
ret = encode_headers(avctx, pict);
if (ret < 0)
return ret;
ret = encode_frame(avctx, pict);
if (ret < 0)
return ret;
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;
return 0;
}
static int apng_do_inverse_blend(AVFrame *output, const AVFrame *input,
APNGFctlChunk *fctl_chunk, uint8_t bpp)
{
// output: background, input: foreground
// output the image such that when blended with the background, will produce the foreground
unsigned int x, y;
unsigned int leftmost_x = input->width;
unsigned int rightmost_x = 0;
unsigned int topmost_y = input->height;
unsigned int bottommost_y = 0;
const uint8_t *input_data = input->data[0];
uint8_t *output_data = output->data[0];
ptrdiff_t input_linesize = input->linesize[0];
ptrdiff_t output_linesize = output->linesize[0];
// Find bounding box of changes
for (y = 0; y < input->height; ++y) {
for (x = 0; x < input->width; ++x) {
if (!memcmp(input_data + bpp * x, output_data + bpp * x, bpp))
continue;
if (x < leftmost_x)
leftmost_x = x;
if (x >= rightmost_x)
rightmost_x = x + 1;
if (y < topmost_y)
topmost_y = y;
if (y >= bottommost_y)
bottommost_y = y + 1;
}
input_data += input_linesize;
output_data += output_linesize;
}
if (leftmost_x == input->width && rightmost_x == 0) {
// Empty frame
// APNG does not support empty frames, so we make it a 1x1 frame
leftmost_x = topmost_y = 0;
rightmost_x = bottommost_y = 1;
}
// Do actual inverse blending
if (fctl_chunk->blend_op == APNG_BLEND_OP_SOURCE) {
output_data = output->data[0];
for (y = topmost_y; y < bottommost_y; ++y) {
memcpy(output_data,
input->data[0] + input_linesize * y + bpp * leftmost_x,
bpp * (rightmost_x - leftmost_x));
output_data += output_linesize;
}
} else { // APNG_BLEND_OP_OVER
size_t transparent_palette_index;
uint32_t *palette;
switch (input->format) {
case AV_PIX_FMT_RGBA64BE:
case AV_PIX_FMT_YA16BE:
case AV_PIX_FMT_RGBA:
case AV_PIX_FMT_GRAY8A:
break;
case AV_PIX_FMT_PAL8:
palette = (uint32_t*)input->data[1];
for (transparent_palette_index = 0; transparent_palette_index < 256; ++transparent_palette_index)
if (palette[transparent_palette_index] >> 24 == 0)
break;
break;
default:
// No alpha, so blending not possible
return -1;
}
for (y = topmost_y; y < bottommost_y; ++y) {
const uint8_t *foreground = input->data[0] + input_linesize * y + bpp * leftmost_x;
uint8_t *background = output->data[0] + output_linesize * y + bpp * leftmost_x;
output_data = output->data[0] + output_linesize * (y - topmost_y);
for (x = leftmost_x; x < rightmost_x; ++x, foreground += bpp, background += bpp, output_data += bpp) {
if (!memcmp(foreground, background, bpp)) {
if (input->format == AV_PIX_FMT_PAL8) {
if (transparent_palette_index == 256) {
// Need fully transparent colour, but none exists
return -1;
}
*output_data = transparent_palette_index;
} else {
memset(output_data, 0, bpp);
}
continue;
}
// Check for special alpha values, since full inverse
// alpha-on-alpha blending is rarely possible, and when
// possible, doesn't compress much better than
// APNG_BLEND_OP_SOURCE blending
switch (input->format) {
case AV_PIX_FMT_RGBA64BE:
if (((uint16_t*)foreground)[3] == 0xffff ||
((uint16_t*)background)[3] == 0)
break;
return -1;
case AV_PIX_FMT_YA16BE:
if (((uint16_t*)foreground)[1] == 0xffff ||
((uint16_t*)background)[1] == 0)
break;
return -1;
case AV_PIX_FMT_RGBA:
if (foreground[3] == 0xff || background[3] == 0)
break;
return -1;
case AV_PIX_FMT_GRAY8A:
if (foreground[1] == 0xff || background[1] == 0)
break;
return -1;
case AV_PIX_FMT_PAL8:
if (palette[*foreground] >> 24 == 0xff ||
palette[*background] >> 24 == 0)
break;
return -1;
}
memmove(output_data, foreground, bpp);
}
}
}
output->width = rightmost_x - leftmost_x;
output->height = bottommost_y - topmost_y;
fctl_chunk->width = output->width;
fctl_chunk->height = output->height;
fctl_chunk->x_offset = leftmost_x;
fctl_chunk->y_offset = topmost_y;
return 0;
}
static int apng_encode_frame(AVCodecContext *avctx, const AVFrame *pict,
APNGFctlChunk *best_fctl_chunk, APNGFctlChunk *best_last_fctl_chunk)
{
PNGEncContext *s = avctx->priv_data;
int ret;
unsigned int y;
AVFrame* diffFrame;
uint8_t bpp = (s->bits_per_pixel + 7) >> 3;
uint8_t *original_bytestream, *original_bytestream_end;
uint8_t *temp_bytestream = 0, *temp_bytestream_end;
uint32_t best_sequence_number;
uint8_t *best_bytestream;
size_t best_bytestream_size = SIZE_MAX;
APNGFctlChunk last_fctl_chunk = *best_last_fctl_chunk;
APNGFctlChunk fctl_chunk = *best_fctl_chunk;
if (avctx->frame_num == 0) {
best_fctl_chunk->width = pict->width;
best_fctl_chunk->height = pict->height;
best_fctl_chunk->x_offset = 0;
best_fctl_chunk->y_offset = 0;
best_fctl_chunk->blend_op = APNG_BLEND_OP_SOURCE;
return encode_frame(avctx, pict);
}
diffFrame = av_frame_alloc();
if (!diffFrame)
return AVERROR(ENOMEM);
diffFrame->format = pict->format;
diffFrame->width = pict->width;
diffFrame->height = pict->height;
if ((ret = av_frame_get_buffer(diffFrame, 0)) < 0)
goto fail;
original_bytestream = s->bytestream;
original_bytestream_end = s->bytestream_end;
temp_bytestream = av_malloc(original_bytestream_end - original_bytestream);
if (!temp_bytestream) {
ret = AVERROR(ENOMEM);
goto fail;
}
temp_bytestream_end = temp_bytestream + (original_bytestream_end - original_bytestream);
for (last_fctl_chunk.dispose_op = 0; last_fctl_chunk.dispose_op < 3; ++last_fctl_chunk.dispose_op) {
// 0: APNG_DISPOSE_OP_NONE
// 1: APNG_DISPOSE_OP_BACKGROUND
// 2: APNG_DISPOSE_OP_PREVIOUS
for (fctl_chunk.blend_op = 0; fctl_chunk.blend_op < 2; ++fctl_chunk.blend_op) {
// 0: APNG_BLEND_OP_SOURCE
// 1: APNG_BLEND_OP_OVER
uint32_t original_sequence_number = s->sequence_number, sequence_number;
uint8_t *bytestream_start = s->bytestream;
size_t bytestream_size;
// Do disposal
if (last_fctl_chunk.dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
diffFrame->width = pict->width;
diffFrame->height = pict->height;
ret = av_frame_copy(diffFrame, s->last_frame);
if (ret < 0)
goto fail;
if (last_fctl_chunk.dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
for (y = last_fctl_chunk.y_offset; y < last_fctl_chunk.y_offset + last_fctl_chunk.height; ++y) {
size_t row_start = diffFrame->linesize[0] * y + bpp * last_fctl_chunk.x_offset;
memset(diffFrame->data[0] + row_start, 0, bpp * last_fctl_chunk.width);
}
}
} else {
if (!s->prev_frame)
continue;
diffFrame->width = pict->width;
diffFrame->height = pict->height;
ret = av_frame_copy(diffFrame, s->prev_frame);
if (ret < 0)
goto fail;
}
// Do inverse blending
if (apng_do_inverse_blend(diffFrame, pict, &fctl_chunk, bpp) < 0)
continue;
// Do encoding
ret = encode_frame(avctx, diffFrame);
sequence_number = s->sequence_number;
s->sequence_number = original_sequence_number;
bytestream_size = s->bytestream - bytestream_start;
s->bytestream = bytestream_start;
if (ret < 0)
goto fail;
if (bytestream_size < best_bytestream_size) {
*best_fctl_chunk = fctl_chunk;
*best_last_fctl_chunk = last_fctl_chunk;
best_sequence_number = sequence_number;
best_bytestream = s->bytestream;
best_bytestream_size = bytestream_size;
if (best_bytestream == original_bytestream) {
s->bytestream = temp_bytestream;
s->bytestream_end = temp_bytestream_end;
} else {
s->bytestream = original_bytestream;
s->bytestream_end = original_bytestream_end;
}
}
}
}
s->sequence_number = best_sequence_number;
s->bytestream = original_bytestream + best_bytestream_size;
s->bytestream_end = original_bytestream_end;
if (best_bytestream != original_bytestream)
memcpy(original_bytestream, best_bytestream, best_bytestream_size);
ret = 0;
fail:
av_freep(&temp_bytestream);
av_frame_free(&diffFrame);
return ret;
}
static int encode_apng(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *pict, int *got_packet)
{
PNGEncContext *s = avctx->priv_data;
int ret;
int enc_row_size;
uint64_t max_packet_size;
APNGFctlChunk fctl_chunk = {0};
if (pict && s->color_type == PNG_COLOR_TYPE_PALETTE) {
uint32_t checksum = ~av_crc(av_crc_get_table(AV_CRC_32_IEEE_LE), ~0U, pict->data[1], 256 * sizeof(uint32_t));
if (avctx->frame_num == 0) {
s->palette_checksum = checksum;
} else if (checksum != s->palette_checksum) {
av_log(avctx, AV_LOG_ERROR,
"Input contains more than one unique palette. APNG does not support multiple palettes.\n");
return -1;
}
}
enc_row_size = deflateBound(&s->zstream.zstream,
(avctx->width * s->bits_per_pixel + 7) >> 3);
max_packet_size =
AV_INPUT_BUFFER_MIN_SIZE + // headers
avctx->height * (
enc_row_size +
(4 + 12) * (((int64_t)enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) // fdAT * ceil(enc_row_size / IOBUF_SIZE)
);
if ((ret = add_icc_profile_size(avctx, pict, &max_packet_size)))
return ret;
if (max_packet_size > INT_MAX)
return AVERROR(ENOMEM);
if (avctx->frame_num == 0) {
if (!pict)
return AVERROR(EINVAL);
s->bytestream = s->extra_data = av_malloc(AV_INPUT_BUFFER_MIN_SIZE);
if (!s->extra_data)
return AVERROR(ENOMEM);
ret = encode_headers(avctx, pict);
if (ret < 0)
return ret;
s->extra_data_size = s->bytestream - s->extra_data;
s->last_frame_packet = av_malloc(max_packet_size);
if (!s->last_frame_packet)
return AVERROR(ENOMEM);
} else if (s->last_frame) {
ret = ff_get_encode_buffer(avctx, pkt, s->last_frame_packet_size, 0);
if (ret < 0)
return ret;
memcpy(pkt->data, s->last_frame_packet, s->last_frame_packet_size);
pkt->pts = s->last_frame->pts;
pkt->duration = s->last_frame->duration;
ret = ff_encode_reordered_opaque(avctx, pkt, s->last_frame);
if (ret < 0)
return ret;
}
if (pict) {
s->bytestream_start =
s->bytestream = s->last_frame_packet;
s->bytestream_end = s->bytestream + max_packet_size;
// We're encoding the frame first, so we have to do a bit of shuffling around
// to have the image data write to the correct place in the buffer
fctl_chunk.sequence_number = s->sequence_number;
++s->sequence_number;
s->bytestream += APNG_FCTL_CHUNK_SIZE + 12;
ret = apng_encode_frame(avctx, pict, &fctl_chunk, &s->last_frame_fctl);
if (ret < 0)
return ret;
fctl_chunk.delay_num = 0; // delay filled in during muxing
fctl_chunk.delay_den = 0;
} else {
s->last_frame_fctl.dispose_op = APNG_DISPOSE_OP_NONE;
}
if (s->last_frame) {
uint8_t* last_fctl_chunk_start = pkt->data;
uint8_t buf[APNG_FCTL_CHUNK_SIZE];
if (!s->extra_data_updated) {
uint8_t *side_data = av_packet_new_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, s->extra_data_size);
if (!side_data)
return AVERROR(ENOMEM);
memcpy(side_data, s->extra_data, s->extra_data_size);
s->extra_data_updated = 1;
}
AV_WB32(buf + 0, s->last_frame_fctl.sequence_number);
AV_WB32(buf + 4, s->last_frame_fctl.width);
AV_WB32(buf + 8, s->last_frame_fctl.height);
AV_WB32(buf + 12, s->last_frame_fctl.x_offset);
AV_WB32(buf + 16, s->last_frame_fctl.y_offset);
AV_WB16(buf + 20, s->last_frame_fctl.delay_num);
AV_WB16(buf + 22, s->last_frame_fctl.delay_den);
buf[24] = s->last_frame_fctl.dispose_op;
buf[25] = s->last_frame_fctl.blend_op;
png_write_chunk(&last_fctl_chunk_start, MKTAG('f', 'c', 'T', 'L'), buf, sizeof(buf));
*got_packet = 1;
}
if (pict) {
if (!s->last_frame) {
s->last_frame = av_frame_alloc();
if (!s->last_frame)
return AVERROR(ENOMEM);
} else if (s->last_frame_fctl.dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
if (!s->prev_frame) {
s->prev_frame = av_frame_alloc();
if (!s->prev_frame)
return AVERROR(ENOMEM);
s->prev_frame->format = pict->format;
s->prev_frame->width = pict->width;
s->prev_frame->height = pict->height;
if ((ret = av_frame_get_buffer(s->prev_frame, 0)) < 0)
return ret;
}
// Do disposal, but not blending
av_frame_copy(s->prev_frame, s->last_frame);
if (s->last_frame_fctl.dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
uint32_t y;
uint8_t bpp = (s->bits_per_pixel + 7) >> 3;
for (y = s->last_frame_fctl.y_offset; y < s->last_frame_fctl.y_offset + s->last_frame_fctl.height; ++y) {
size_t row_start = s->prev_frame->linesize[0] * y + bpp * s->last_frame_fctl.x_offset;
memset(s->prev_frame->data[0] + row_start, 0, bpp * s->last_frame_fctl.width);
}
}
}
av_frame_unref(s->last_frame);
ret = av_frame_ref(s->last_frame, pict);
if (ret < 0)
return ret;
s->last_frame_fctl = fctl_chunk;
s->last_frame_packet_size = s->bytestream - s->bytestream_start;
} else {
av_frame_free(&s->last_frame);
}
return 0;
}
static av_cold int png_enc_init(AVCodecContext *avctx)
{
PNGEncContext *s = avctx->priv_data;
int compression_level;
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;
}
ff_llvidencdsp_init(&s->llvidencdsp);
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;
}
s->is_progressive = !!(avctx->flags & AV_CODEC_FLAG_INTERLACED_DCT);
switch (avctx->pix_fmt) {
case AV_PIX_FMT_RGBA64BE:
s->bit_depth = 16;
s->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case AV_PIX_FMT_RGB48BE:
s->bit_depth = 16;
s->color_type = PNG_COLOR_TYPE_RGB;
break;
case AV_PIX_FMT_RGBA:
s->bit_depth = 8;
s->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case AV_PIX_FMT_RGB24:
s->bit_depth = 8;
s->color_type = PNG_COLOR_TYPE_RGB;
break;
case AV_PIX_FMT_GRAY16BE:
s->bit_depth = 16;
s->color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_GRAY8:
s->bit_depth = 8;
s->color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_GRAY8A:
s->bit_depth = 8;
s->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
break;
case AV_PIX_FMT_YA16BE:
s->bit_depth = 16;
s->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
break;
case AV_PIX_FMT_MONOBLACK:
s->bit_depth = 1;
s->color_type = PNG_COLOR_TYPE_GRAY;
break;
case AV_PIX_FMT_PAL8:
s->bit_depth = 8;
s->color_type = PNG_COLOR_TYPE_PALETTE;
break;
default:
return -1;
}
s->bits_per_pixel = ff_png_get_nb_channels(s->color_type) * s->bit_depth;
compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT
? Z_DEFAULT_COMPRESSION
: av_clip(avctx->compression_level, 0, 9);
return ff_deflate_init(&s->zstream, compression_level, avctx);
}
static av_cold int png_enc_close(AVCodecContext *avctx)
{
PNGEncContext *s = avctx->priv_data;
ff_deflate_end(&s->zstream);
av_frame_free(&s->last_frame);
av_frame_free(&s->prev_frame);
av_freep(&s->last_frame_packet);
av_freep(&s->extra_data);
s->extra_data_size = 0;
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},
{ "pred", "Prediction method", OFFSET(filter_type), AV_OPT_TYPE_INT, { .i64 = PNG_FILTER_VALUE_NONE }, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED, VE, "pred" },
{ "none", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_NONE }, INT_MIN, INT_MAX, VE, "pred" },
{ "sub", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_SUB }, INT_MIN, INT_MAX, VE, "pred" },
{ "up", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_UP }, INT_MIN, INT_MAX, VE, "pred" },
{ "avg", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_AVG }, INT_MIN, INT_MAX, VE, "pred" },
{ "paeth", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_PAETH }, INT_MIN, INT_MAX, VE, "pred" },
{ "mixed", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = PNG_FILTER_VALUE_MIXED }, INT_MIN, INT_MAX, VE, "pred" },
{ NULL},
};
static const AVClass pngenc_class = {
.class_name = "(A)PNG encoder",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
const FFCodec ff_png_encoder = {
.p.name = "png",
CODEC_LONG_NAME("PNG (Portable Network Graphics) image"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_PNG,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
.priv_data_size = sizeof(PNGEncContext),
.init = png_enc_init,
.close = png_enc_close,
FF_CODEC_ENCODE_CB(encode_png),
.p.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_YA16BE,
AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
},
.p.priv_class = &pngenc_class,
.caps_internal = FF_CODEC_CAP_ICC_PROFILES,
};
const FFCodec ff_apng_encoder = {
.p.name = "apng",
CODEC_LONG_NAME("APNG (Animated Portable Network Graphics) image"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_APNG,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |
AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
.priv_data_size = sizeof(PNGEncContext),
.init = png_enc_init,
.close = png_enc_close,
FF_CODEC_ENCODE_CB(encode_apng),
.p.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_YA16BE,
AV_PIX_FMT_NONE
},
.p.priv_class = &pngenc_class,
.caps_internal = FF_CODEC_CAP_ICC_PROFILES,
};
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