BMP image decoder

Originally committed as revision 4711 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 251 insertions, 0 deletions

diff --git a/libavcodec/bmp.c b/libavcodec/bmp.c
new file mode 100644
index 0000000000..bae3655add
--- /dev/null
+++ b/libavcodec/bmp.c
@@ -0,0 +1,251 @@
+/*
+ * BMP image format
+ * Copyright (c) 2005 Mans Rullgard
+ *
+ * This library 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 of the License, or (at your option) any later version.
+ *
+ * This library 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "avcodec.h"
+#include "bitstream.h"
+#include "bswap.h"
+
+typedef struct BMPContext {
+    AVFrame picture;
+} BMPContext;
+
+#define BMP_RGB       0
+#define BMP_RLE8      1
+#define BMP_RLE4      2
+#define BMP_BITFIELDS 3
+
+#define read16(bits) bswap_16(get_bits(bits, 16))
+#define read32(bits) bswap_32(get_bits_long(bits, 32))
+
+static int bmp_decode_init(AVCodecContext *avctx){
+    BMPContext *s = avctx->priv_data;
+
+    avcodec_get_frame_defaults((AVFrame*)&s->picture);
+    avctx->coded_frame = (AVFrame*)&s->picture;
+
+    return 0;
+}
+
+static int bmp_decode_frame(AVCodecContext *avctx, 
+                            void *data, int *data_size,
+                            uint8_t *buf, int buf_size)
+{
+    BMPContext *s = avctx->priv_data;
+    AVFrame *picture = data;
+    AVFrame *p = &s->picture;
+    GetBitContext bits;
+    unsigned int fsize, hsize;
+    int width, height;
+    unsigned int depth;
+    unsigned int comp;
+    unsigned int ihsize;
+    int i, j, n, linesize;
+    uint32_t rgb[3];
+    uint8_t *ptr;
+    int dsize;
+
+    if(buf_size < 14){
+        av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
+        return -1;
+    }
+
+    init_get_bits(&bits, buf, buf_size);
+
+    if(get_bits(&bits, 16) != 0x424d){ /* 'BM' */
+        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
+        return -1;
+    }
+
+    fsize = read32(&bits);
+    if(buf_size < fsize){
+        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
+               buf_size, fsize);
+        return -1;
+    }
+
+    skip_bits(&bits, 16);       /* reserved1 */
+    skip_bits(&bits, 16);       /* reserved2 */
+
+    hsize = read32(&bits); /* header size */
+    if(fsize <= hsize){
+        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
+               fsize, hsize);
+        return -1;
+    }
+
+    ihsize = read32(&bits);       /* more header size */
+    if(ihsize + 14 > hsize){
+        av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
+        return -1;
+    }
+
+    width = read32(&bits);
+    height = read32(&bits);
+
+    if(read16(&bits) != 1){ /* planes */
+        av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
+        return -1;
+    }
+
+    depth = read16(&bits);
+
+    if(ihsize > 16)
+        comp = read32(&bits);
+    else
+        comp = BMP_RGB;
+
+    if(comp != BMP_RGB && comp != BMP_BITFIELDS){
+        av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
+        return -1;
+    }
+
+    if(comp == BMP_BITFIELDS){
+        skip_bits(&bits, 20 * 8);
+        rgb[0] = read32(&bits);
+        rgb[1] = read32(&bits);
+        rgb[2] = read32(&bits);
+    }
+
+    avctx->codec_id = CODEC_ID_BMP;
+    avctx->width = width;
+    avctx->height = height > 0? height: -height;
+
+    avctx->pix_fmt = PIX_FMT_NONE;
+
+    switch(depth){
+    case 32:
+        if(comp == BMP_BITFIELDS){
+            rgb[0] = (rgb[0] >> 15) & 3;
+            rgb[1] = (rgb[1] >> 15) & 3;
+            rgb[2] = (rgb[2] >> 15) & 3;
+
+            if(rgb[0] + rgb[1] + rgb[2] != 3 ||
+               rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){
+                break;
+            }
+        } else {
+            rgb[0] = 2;
+            rgb[1] = 1;
+            rgb[2] = 0;
+        }
+
+        avctx->pix_fmt = PIX_FMT_BGR24;
+        break;
+    case 24:
+        avctx->pix_fmt = PIX_FMT_BGR24;
+        break;
+    case 16:
+        if(comp == BMP_RGB)
+            avctx->pix_fmt = PIX_FMT_RGB555;
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
+        return -1;
+    }
+
+    if(avctx->pix_fmt == PIX_FMT_NONE){
+        av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
+        return -1;
+    }
+
+    p->reference = 0;
+    if(avctx->get_buffer(avctx, p) < 0){
+        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+        return -1;
+    }
+    p->pict_type = FF_I_TYPE;
+    p->key_frame = 1;
+
+    buf += hsize;
+    dsize = buf_size - hsize;
+
+    n = avctx->width * (depth / 8);
+
+    if(n * avctx->height > dsize){
+        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
+               dsize, n * avctx->height);
+        return -1;
+    }
+
+    if(height > 0){
+        ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
+        linesize = -p->linesize[0];
+    } else {
+        ptr = p->data[0];
+        linesize = p->linesize[0];
+    }
+
+    switch(depth){
+    case 24:
+        for(i = 0; i < avctx->height; i++){
+            memcpy(ptr, buf, n);
+            buf += n;
+            ptr += linesize;
+        }
+        break;
+    case 16:
+        for(i = 0; i < avctx->height; i++){
+            uint16_t *src = (uint16_t *) buf;
+            uint16_t *dst = (uint16_t *) ptr;
+
+            for(j = 0; j < avctx->width; j++)
+                *dst++ = le2me_16(*src++);
+
+            buf += n;
+            ptr += linesize;
+        }
+        break;
+    case 32:
+        for(i = 0; i < avctx->height; i++){
+            uint8_t *src = buf;
+            uint8_t *dst = ptr;
+
+            for(j = 0; j < avctx->width; j++){
+                dst[0] = src[rgb[2]];
+                dst[1] = src[rgb[1]];
+                dst[2] = src[rgb[0]];
+                dst += 3;
+                src += 4;
+            }
+
+            buf += n;
+            ptr += linesize;
+        }
+        break;
+    default:
+        av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
+        return -1;
+    }
+
+    *picture = s->picture;
+    *data_size = sizeof(AVPicture);
+
+    return buf_size;
+}
+
+AVCodec bmp_decoder = {
+    "bmp",
+    CODEC_TYPE_VIDEO,
+    CODEC_ID_BMP,
+    sizeof(BMPContext),
+    bmp_decode_init,
+    NULL,
+    NULL,
+    bmp_decode_frame
+};