3 * Copyright (c) 2003 Fabrice Bellard.
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "bytestream.h"
26 * - add 2, 4 and 16 bit depth support
27 * - use filters when generating a png (better compression)
34 #define IOBUF_SIZE 4096
36 typedef struct PNGEncContext {
38 uint8_t *bytestream_start;
39 uint8_t *bytestream_end;
43 uint8_t buf[IOBUF_SIZE];
46 static void png_get_interlaced_row(uint8_t *dst, int row_size,
47 int bits_per_pixel, int pass,
48 const uint8_t *src, int width)
50 int x, mask, dst_x, j, b, bpp;
54 mask = ff_png_pass_mask[pass];
55 switch(bits_per_pixel) {
57 memset(dst, 0, row_size);
59 for(x = 0; x < width; x++) {
61 if ((mask << j) & 0x80) {
62 b = (src[x >> 3] >> (7 - j)) & 1;
63 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
69 bpp = bits_per_pixel >> 3;
72 for(x = 0; x < width; x++) {
74 if ((mask << j) & 0x80) {
84 static void convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width)
91 for(j = 0; j < width; j++) {
92 v = ((const uint32_t *)src)[j];
101 static void png_write_chunk(uint8_t **f, uint32_t tag,
102 const uint8_t *buf, int length)
107 bytestream_put_be32(f, length);
108 crc = crc32(0, Z_NULL, 0);
109 AV_WL32(tagbuf, tag);
110 crc = crc32(crc, tagbuf, 4);
111 bytestream_put_be32(f, bswap_32(tag));
113 crc = crc32(crc, buf, length);
114 memcpy(*f, buf, length);
117 bytestream_put_be32(f, crc);
120 /* XXX: do filtering */
121 static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
125 s->zstream.avail_in = size;
126 s->zstream.next_in = (uint8_t *)data;
127 while (s->zstream.avail_in > 0) {
128 ret = deflate(&s->zstream, Z_NO_FLUSH);
131 if (s->zstream.avail_out == 0) {
132 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
133 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
134 s->zstream.avail_out = IOBUF_SIZE;
135 s->zstream.next_out = s->buf;
141 static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
142 PNGEncContext *s = avctx->priv_data;
143 AVFrame *pict = data;
144 AVFrame * const p= (AVFrame*)&s->picture;
145 int bit_depth, color_type, y, len, row_size, ret, is_progressive;
146 int bits_per_pixel, pass_row_size;
147 int compression_level;
149 uint8_t *crow_buf = NULL;
150 uint8_t *tmp_buf = NULL;
153 p->pict_type= FF_I_TYPE;
158 s->bytestream_end= buf+buf_size;
160 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
161 switch(avctx->pix_fmt) {
164 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
168 color_type = PNG_COLOR_TYPE_RGB;
172 color_type = PNG_COLOR_TYPE_GRAY;
174 case PIX_FMT_MONOBLACK:
176 color_type = PNG_COLOR_TYPE_GRAY;
180 color_type = PNG_COLOR_TYPE_PALETTE;
185 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
186 row_size = (avctx->width * bits_per_pixel + 7) >> 3;
188 s->zstream.zalloc = ff_png_zalloc;
189 s->zstream.zfree = ff_png_zfree;
190 s->zstream.opaque = NULL;
191 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
192 Z_DEFAULT_COMPRESSION :
193 av_clip(avctx->compression_level, 0, 9);
194 ret = deflateInit2(&s->zstream, compression_level,
195 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
198 crow_buf = av_malloc(row_size + 1);
201 if (is_progressive) {
202 tmp_buf = av_malloc(row_size + 1);
207 /* write png header */
208 memcpy(s->bytestream, ff_pngsig, 8);
211 AV_WB32(s->buf, avctx->width);
212 AV_WB32(s->buf + 4, avctx->height);
213 s->buf[8] = bit_depth;
214 s->buf[9] = color_type;
215 s->buf[10] = 0; /* compression type */
216 s->buf[11] = 0; /* filter type */
217 s->buf[12] = is_progressive; /* interlace type */
219 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
221 /* put the palette if needed */
222 if (color_type == PNG_COLOR_TYPE_PALETTE) {
223 int has_alpha, alpha, i;
228 palette = (uint32_t *)p->data[1];
230 alpha_ptr = s->buf + 256 * 3;
232 for(i = 0; i < 256; i++) {
235 if (alpha && alpha != 0xff)
237 *alpha_ptr++ = alpha;
238 bytestream_put_be24(&ptr, v);
240 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
242 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
246 /* now put each row */
247 s->zstream.avail_out = IOBUF_SIZE;
248 s->zstream.next_out = s->buf;
249 if (is_progressive) {
253 for(pass = 0; pass < NB_PASSES; pass++) {
254 /* NOTE: a pass is completely omited if no pixels would be
256 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
257 if (pass_row_size > 0) {
258 for(y = 0; y < avctx->height; y++) {
259 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
260 ptr = p->data[0] + y * p->linesize[0];
261 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
262 convert_from_rgb32(tmp_buf, ptr, avctx->width);
267 png_get_interlaced_row(crow_buf + 1, pass_row_size,
268 bits_per_pixel, pass,
270 crow_buf[0] = PNG_FILTER_VALUE_NONE;
271 png_write_row(s, crow_buf, pass_row_size + 1);
277 for(y = 0; y < avctx->height; y++) {
278 ptr = p->data[0] + y * p->linesize[0];
279 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
280 convert_from_rgb32(crow_buf + 1, ptr, avctx->width);
282 memcpy(crow_buf + 1, ptr, row_size);
283 crow_buf[0] = PNG_FILTER_VALUE_NONE;
284 png_write_row(s, crow_buf, row_size + 1);
287 /* compress last bytes */
289 ret = deflate(&s->zstream, Z_FINISH);
290 if (ret == Z_OK || ret == Z_STREAM_END) {
291 len = IOBUF_SIZE - s->zstream.avail_out;
292 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
293 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
295 s->zstream.avail_out = IOBUF_SIZE;
296 s->zstream.next_out = s->buf;
297 if (ret == Z_STREAM_END)
303 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
305 ret = s->bytestream - s->bytestream_start;
309 deflateEnd(&s->zstream);
316 static int png_enc_init(AVCodecContext *avctx){
317 PNGEncContext *s = avctx->priv_data;
319 avcodec_get_frame_defaults((AVFrame*)&s->picture);
320 avctx->coded_frame= (AVFrame*)&s->picture;
325 AVCodec png_encoder = {
329 sizeof(PNGEncContext),
333 .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, -1},