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"
23 #include "libavutil/avassert.h"
25 #include "bytestream.h"
29 typedef struct SgiState {
30 AVCodecContext *avctx;
34 unsigned int bytes_per_channel;
40 * Expand an RLE row into a channel.
41 * @param s the current image state
42 * @param out_buf Points to one line after the output buffer.
43 * @param len length of out_buf in bytes
44 * @param pixelstride pixel stride of input buffer
45 * @return size of output in bytes, else return error code.
47 static int expand_rle_row(SgiState *s, uint8_t *out_buf,
48 int len, int pixelstride)
50 unsigned char pixel, count;
51 unsigned char *orig = out_buf;
52 uint8_t *out_end = out_buf + len;
54 while (out_buf < out_end) {
55 if (bytestream2_get_bytes_left(&s->g) < 1)
56 return AVERROR_INVALIDDATA;
57 pixel = bytestream2_get_byteu(&s->g);
58 if (!(count = (pixel & 0x7f))) {
62 /* Check for buffer overflow. */
63 if (out_end - out_buf <= pixelstride * (count - 1)) {
64 av_log(s->avctx, AV_LOG_ERROR, "Invalid pixel count.\n");
65 return AVERROR_INVALIDDATA;
70 *out_buf = bytestream2_get_byte(&s->g);
71 out_buf += pixelstride;
74 pixel = bytestream2_get_byte(&s->g);
78 out_buf += pixelstride;
82 return (out_buf - orig) / pixelstride;
86 * Read a run length encoded SGI image.
87 * @param out_buf output buffer
88 * @param s the current image state
89 * @return 0 if no error, else return error code.
91 static int read_rle_sgi(uint8_t *out_buf, SgiState *s)
94 unsigned int len = s->height * s->depth * 4;
95 GetByteContext g_table = s->g;
97 unsigned int start_offset;
99 /* size of RLE offset and length tables */
100 if (len * 2 > bytestream2_get_bytes_left(&s->g)) {
101 return AVERROR_INVALIDDATA;
104 for (z = 0; z < s->depth; z++) {
106 for (y = 0; y < s->height; y++) {
107 dest_row -= s->linesize;
108 start_offset = bytestream2_get_be32(&g_table);
109 bytestream2_seek(&s->g, start_offset, SEEK_SET);
110 if (expand_rle_row(s, dest_row + z, s->width*s->depth,
111 s->depth) != s->width) {
112 return AVERROR_INVALIDDATA;
120 * Read an uncompressed SGI image.
121 * @param out_buf output buffer
122 * @param s the current image state
123 * @return 0 if read success, else return error code.
125 static int read_uncompressed_sgi(unsigned char* out_buf, SgiState *s)
128 unsigned int offset = s->height * s->width * s->bytes_per_channel;
129 GetByteContext gp[4];
132 /* Test buffer size. */
133 if (offset * s->depth > bytestream2_get_bytes_left(&s->g))
134 return AVERROR_INVALIDDATA;
136 /* Create a reader for each plane */
137 for (z = 0; z < s->depth; z++) {
139 bytestream2_skip(&gp[z], z * offset);
142 for (y = s->height - 1; y >= 0; y--) {
143 out_end = out_buf + (y * s->linesize);
144 if (s->bytes_per_channel == 1) {
145 for (x = s->width; x > 0; x--)
146 for (z = 0; z < s->depth; z++)
147 *out_end++ = bytestream2_get_byteu(&gp[z]);
149 uint16_t *out16 = (uint16_t *)out_end;
150 for (x = s->width; x > 0; x--)
151 for (z = 0; z < s->depth; z++)
152 *out16++ = bytestream2_get_ne16u(&gp[z]);
158 static int decode_frame(AVCodecContext *avctx,
159 void *data, int *got_frame,
162 SgiState *s = avctx->priv_data;
164 unsigned int dimension, rle;
166 uint8_t *out_buf, *out_end;
168 bytestream2_init(&s->g, avpkt->data, avpkt->size);
169 if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) {
170 av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
171 return AVERROR_INVALIDDATA;
174 /* Test for SGI magic. */
175 if (bytestream2_get_be16u(&s->g) != SGI_MAGIC) {
176 av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
177 return AVERROR_INVALIDDATA;
180 rle = bytestream2_get_byteu(&s->g);
181 s->bytes_per_channel = bytestream2_get_byteu(&s->g);
182 dimension = bytestream2_get_be16u(&s->g);
183 s->width = bytestream2_get_be16u(&s->g);
184 s->height = bytestream2_get_be16u(&s->g);
185 s->depth = bytestream2_get_be16u(&s->g);
187 if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) {
188 av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
189 return AVERROR_INVALIDDATA;
192 /* Check for supported image dimensions. */
193 if (dimension != 2 && dimension != 3) {
194 av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
195 return AVERROR_INVALIDDATA;
198 if (s->depth == SGI_GRAYSCALE) {
199 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
200 } else if (s->depth == SGI_RGB) {
201 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGB48BE : AV_PIX_FMT_RGB24;
202 } else if (s->depth == SGI_RGBA) {
203 avctx->pix_fmt = s->bytes_per_channel == 2 ? AV_PIX_FMT_RGBA64BE : AV_PIX_FMT_RGBA;
205 av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
206 return AVERROR_INVALIDDATA;
209 ret = ff_set_dimensions(avctx, s->width, s->height);
213 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
216 p->pict_type = AV_PICTURE_TYPE_I;
218 out_buf = p->data[0];
220 out_end = out_buf + p->linesize[0] * s->height;
222 s->linesize = p->linesize[0];
225 bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET);
227 ret = read_rle_sgi(out_end, s);
229 ret = read_uncompressed_sgi(out_buf, s);
238 static av_cold int sgi_decode_init(AVCodecContext *avctx)
240 SgiState *s = avctx->priv_data;
247 AVCodec ff_sgi_decoder = {
249 .long_name = NULL_IF_CONFIG_SMALL("SGI image"),
250 .type = AVMEDIA_TYPE_VIDEO,
251 .id = AV_CODEC_ID_SGI,
252 .priv_data_size = sizeof(SgiState),
253 .decode = decode_frame,
254 .init = sgi_decode_init,
255 .capabilities = CODEC_CAP_DR1,