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Diffstat (limited to 'ffmpeg/libavcodec/pngenc.c')
-rw-r--r--ffmpeg/libavcodec/pngenc.c480
1 files changed, 480 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/pngenc.c b/ffmpeg/libavcodec/pngenc.c
new file mode 100644
index 0000000..a401c78
--- /dev/null
+++ b/ffmpeg/libavcodec/pngenc.c
@@ -0,0 +1,480 @@
+/*
+ * 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"
+
+/* TODO:
+ * - add 2, 4 and 16 bit depth support
+ */
+
+#include <zlib.h>
+
+//#define DEBUG
+
+#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;
+
+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;
+
+ mask = (int[]){0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff}[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 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;
+ 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;
+ AVFrame * const p= &s->picture;
+ 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;
+
+ *p = *pict;
+ p->pict_type= AV_PICTURE_TYPE_I;
+ p->key_frame= 1;
+
+ 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);
+
+ 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;
+ }
+
+ avcodec_get_frame_defaults(&s->picture);
+ avctx->coded_frame= &s->picture;
+ 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;
+
+ return 0;
+}
+
+AVCodec ff_png_encoder = {
+ .name = "png",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .id = AV_CODEC_ID_PNG,
+ .priv_data_size = sizeof(PNGEncContext),
+ .init = png_enc_init,
+ .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
+ },
+ .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
+};
generated by cgit v1.2.3 (git 2.39.1) at 2025-12-06 14:09:13 +0000