separate en/decoder specific parts from png.c

Originally committed as revision 9686 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 309 insertions, 0 deletions

diff --git a/libavcodec/pngenc.c b/libavcodec/pngenc.c
new file mode 100644
index 0000000000..d4cd6deae3
--- /dev/null
+++ b/libavcodec/pngenc.c
@@ -0,0 +1,309 @@
+/*
+ * 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 "bytestream.h"
+#include "png.h"
+
+/* TODO:
+ * - add 2, 4 and 16 bit depth support
+ * - use filters when generating a png (better compression)
+ */
+
+#include <zlib.h>
+
+//#define DEBUG
+
+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 = ff_png_pass_mask[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 convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width)
+{
+    uint8_t *d;
+    int j;
+    unsigned int v;
+
+    d = dst;
+    for(j = 0; j < width; j++) {
+        v = ((const uint32_t *)src)[j];
+        d[0] = v >> 16;
+        d[1] = v >> 8;
+        d[2] = v;
+        d[3] = v >> 24;
+        d += 4;
+    }
+}
+
+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, bswap_32(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(PNGContext *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, unsigned char *buf, int buf_size, void *data){
+    PNGContext *s = avctx->priv_data;
+    AVFrame *pict = data;
+    AVFrame * const p= (AVFrame*)&s->picture;
+    int bit_depth, color_type, y, len, row_size, ret, is_progressive;
+    int bits_per_pixel, pass_row_size;
+    uint8_t *ptr;
+    uint8_t *crow_buf = NULL;
+    uint8_t *tmp_buf = NULL;
+
+    *p = *pict;
+    p->pict_type= FF_I_TYPE;
+    p->key_frame= 1;
+
+    s->bytestream_start=
+    s->bytestream= buf;
+    s->bytestream_end= buf+buf_size;
+
+    is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
+    switch(avctx->pix_fmt) {
+    case PIX_FMT_RGB32:
+        bit_depth = 8;
+        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+        break;
+    case PIX_FMT_RGB24:
+        bit_depth = 8;
+        color_type = PNG_COLOR_TYPE_RGB;
+        break;
+    case PIX_FMT_GRAY8:
+        bit_depth = 8;
+        color_type = PNG_COLOR_TYPE_GRAY;
+        break;
+    case PIX_FMT_MONOBLACK:
+        bit_depth = 1;
+        color_type = PNG_COLOR_TYPE_GRAY;
+        break;
+    case 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;
+    ret = deflateInit2(&s->zstream, Z_DEFAULT_COMPRESSION,
+                       Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
+    if (ret != Z_OK)
+        return -1;
+    crow_buf = av_malloc(row_size + 1);
+    if (!crow_buf)
+        goto fail;
+    if (is_progressive) {
+        tmp_buf = av_malloc(row_size + 1);
+        if (!tmp_buf)
+            goto fail;
+    }
+
+    /* write png header */
+    memcpy(s->bytestream, ff_pngsig, 8);
+    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);
+
+    /* 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 && 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) {
+        uint8_t *ptr1;
+        int pass;
+
+        for(pass = 0; pass < NB_PASSES; pass++) {
+            /* NOTE: a pass is completely omited 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) {
+                for(y = 0; y < avctx->height; y++) {
+                    if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
+                        ptr = p->data[0] + y * p->linesize[0];
+                        if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
+                            convert_from_rgb32(tmp_buf, ptr, avctx->width);
+                            ptr1 = tmp_buf;
+                        } else {
+                            ptr1 = ptr;
+                        }
+                        png_get_interlaced_row(crow_buf + 1, 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);
+                    }
+                }
+            }
+        }
+    } else {
+        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);
+        }
+    }
+    /* 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);
+
+    ret = s->bytestream - s->bytestream_start;
+ the_end:
+    av_free(crow_buf);
+    av_free(tmp_buf);
+    deflateEnd(&s->zstream);
+    return ret;
+ fail:
+    ret = -1;
+    goto the_end;
+}
+
+AVCodec png_encoder = {
+    "png",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_PNG,
+    sizeof(PNGContext),
+    ff_png_common_init,
+    encode_frame,
+    NULL, //encode_end,
+    .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, -1},
+};