3 * Todd Kirby <doubleshot@pacbell.net>
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 "libavutil/imgutils.h"
24 #include "bytestream.h"
27 typedef struct SgiState {
32 unsigned int bytes_per_channel;
37 * Expand an RLE row into a channel.
38 * @param in_buf input buffer
39 * @param in_end end of input buffer
40 * @param out_buf Points to one line after the output buffer.
41 * @param out_end end of line in output buffer
42 * @param pixelstride pixel stride of input buffer
43 * @return size of output in bytes, -1 if buffer overflows
45 static int expand_rle_row(const uint8_t *in_buf, const uint8_t* in_end,
46 unsigned char *out_buf, uint8_t* out_end, int pixelstride)
48 unsigned char pixel, count;
49 unsigned char *orig = out_buf;
52 if(in_buf + 1 > in_end) return -1;
53 pixel = bytestream_get_byte(&in_buf);
54 if (!(count = (pixel & 0x7f))) {
55 return (out_buf - orig) / pixelstride;
58 /* Check for buffer overflow. */
59 if(out_buf + pixelstride * count >= out_end) return -1;
63 *out_buf = bytestream_get_byte(&in_buf);
64 out_buf += pixelstride;
67 pixel = bytestream_get_byte(&in_buf);
71 out_buf += pixelstride;
78 * Read a run length encoded SGI image.
79 * @param out_buf output buffer
80 * @param in_buf input buffer
81 * @param in_end end of input buffer
82 * @param s the current image state
83 * @return 0 if no error, else return error number.
85 static int read_rle_sgi(unsigned char* out_buf, const uint8_t *in_buf,
86 const uint8_t *in_end, SgiState* s)
89 unsigned int len = s->height * s->depth * 4;
90 const uint8_t *start_table = in_buf;
92 unsigned int start_offset;
94 /* size of RLE offset and length tables */
95 if(len * 2 > in_end - in_buf) {
96 return AVERROR_INVALIDDATA;
99 in_buf -= SGI_HEADER_SIZE;
100 for (z = 0; z < s->depth; z++) {
102 for (y = 0; y < s->height; y++) {
103 dest_row -= s->linesize;
104 start_offset = bytestream_get_be32(&start_table);
105 if(start_offset > in_end - in_buf) {
106 return AVERROR_INVALIDDATA;
108 if (expand_rle_row(in_buf + start_offset, in_end, dest_row + z,
109 dest_row + FFABS(s->linesize), s->depth) != s->width)
110 return AVERROR_INVALIDDATA;
117 * Read an uncompressed SGI image.
118 * @param out_buf output buffer
119 * @param out_end end ofoutput buffer
120 * @param in_buf input buffer
121 * @param in_end end of input buffer
122 * @param s the current image state
123 * @return 0 if read success, otherwise return -1.
125 static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end,
126 const uint8_t *in_buf, const uint8_t *in_end, SgiState* s)
130 unsigned int offset = s->height * s->width * s->bytes_per_channel;
132 /* Test buffer size. */
133 if (offset * s->depth > in_end - in_buf) {
137 for (y = s->height - 1; y >= 0; y--) {
138 out_end = out_buf + (y * s->linesize);
139 for (x = s->width; x > 0; x--) {
140 ptr = in_buf += s->bytes_per_channel;
141 for(z = 0; z < s->depth; z ++) {
142 memcpy(out_end, ptr, s->bytes_per_channel);
143 out_end += s->bytes_per_channel;
151 static int decode_frame(AVCodecContext *avctx,
152 void *data, int *data_size,
155 const uint8_t *in_buf = avpkt->data;
156 int buf_size = avpkt->size;
157 SgiState *s = avctx->priv_data;
158 AVFrame *picture = data;
159 AVFrame *p = &s->picture;
160 const uint8_t *in_end = in_buf + buf_size;
161 unsigned int dimension, rle;
163 uint8_t *out_buf, *out_end;
165 if (buf_size < SGI_HEADER_SIZE){
166 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", buf_size);
170 /* Test for SGI magic. */
171 if (bytestream_get_be16(&in_buf) != SGI_MAGIC) {
172 av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
176 rle = bytestream_get_byte(&in_buf);
177 s->bytes_per_channel = bytestream_get_byte(&in_buf);
178 dimension = bytestream_get_be16(&in_buf);
179 s->width = bytestream_get_be16(&in_buf);
180 s->height = bytestream_get_be16(&in_buf);
181 s->depth = bytestream_get_be16(&in_buf);
183 if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
184 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
188 /* Check for supported image dimensions. */
189 if (dimension != 2 && dimension != 3) {
190 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
194 if (s->depth == SGI_GRAYSCALE) {
195 avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8;
196 } else if (s->depth == SGI_RGB) {
197 avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24;
198 } else if (s->depth == SGI_RGBA && s->bytes_per_channel == 1) {
199 avctx->pix_fmt = PIX_FMT_RGBA;
201 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
205 if (av_image_check_size(s->width, s->height, 0, avctx))
207 avcodec_set_dimensions(avctx, s->width, s->height);
210 avctx->release_buffer(avctx, p);
213 if (avctx->get_buffer(avctx, p) < 0) {
214 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed.\n");
218 p->pict_type = AV_PICTURE_TYPE_I;
220 out_buf = p->data[0];
222 out_end = out_buf + p->linesize[0] * s->height;
224 s->linesize = p->linesize[0];
227 in_buf += SGI_HEADER_SIZE - 12;
229 ret = read_rle_sgi(out_end, in_buf, in_end, s);
231 ret = read_uncompressed_sgi(out_buf, out_end, in_buf, in_end, s);
235 *picture = s->picture;
236 *data_size = sizeof(AVPicture);
243 static av_cold int sgi_init(AVCodecContext *avctx){
244 SgiState *s = avctx->priv_data;
246 avcodec_get_frame_defaults(&s->picture);
247 avctx->coded_frame = &s->picture;
252 static av_cold int sgi_end(AVCodecContext *avctx)
254 SgiState * const s = avctx->priv_data;
256 if (s->picture.data[0])
257 avctx->release_buffer(avctx, &s->picture);
262 AVCodec ff_sgi_decoder = {
264 .type = AVMEDIA_TYPE_VIDEO,
266 .priv_data_size = sizeof(SgiState),
269 .decode = decode_frame,
270 .long_name = NULL_IF_CONFIG_SMALL("SGI image"),