/* * SGI image decoder * Todd Kirby <doubleshot@pacbell.net> * * 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 "libavutil/imgutils.h" #include "libavutil/avassert.h" #include "avcodec.h" #include "bytestream.h" #include "sgi.h" typedef struct SgiState { AVFrame picture; unsigned int width; unsigned int height; unsigned int depth; unsigned int bytes_per_channel; int linesize; GetByteContext g; } SgiState; /** * Expand an RLE row into a channel. * @param s the current image state * @param out_buf Points to one line after the output buffer. * @param out_end end of line in output buffer * @param pixelstride pixel stride of input buffer * @return size of output in bytes, -1 if buffer overflows */ static int expand_rle_row(SgiState *s, uint8_t *out_buf, uint8_t *out_end, int pixelstride) { unsigned char pixel, count; unsigned char *orig = out_buf; while (1) { if (bytestream2_get_bytes_left(&s->g) < 1) return AVERROR_INVALIDDATA; pixel = bytestream2_get_byteu(&s->g); if (!(count = (pixel & 0x7f))) { return (out_buf - orig) / pixelstride; } /* Check for buffer overflow. */ if(out_buf + pixelstride * count >= out_end) return -1; if (pixel & 0x80) { while (count--) { *out_buf = bytestream2_get_byte(&s->g); out_buf += pixelstride; } } else { pixel = bytestream2_get_byte(&s->g); while (count--) { *out_buf = pixel; out_buf += pixelstride; } } } } /** * Read a run length encoded SGI image. * @param out_buf output buffer * @param s the current image state * @return 0 if no error, else return error number. */ static int read_rle_sgi(uint8_t *out_buf, SgiState *s) { uint8_t *dest_row; unsigned int len = s->height * s->depth * 4; GetByteContext g_table = s->g; unsigned int y, z; unsigned int start_offset; /* size of RLE offset and length tables */ if (len * 2 > bytestream2_get_bytes_left(&s->g)) { return AVERROR_INVALIDDATA; } for (z = 0; z < s->depth; z++) { dest_row = out_buf; for (y = 0; y < s->height; y++) { dest_row -= s->linesize; start_offset = bytestream2_get_be32(&g_table); bytestream2_seek(&s->g, start_offset, SEEK_SET); if (expand_rle_row(s, dest_row + z, dest_row + FFABS(s->linesize), s->depth) != s->width) { return AVERROR_INVALIDDATA; } } } return 0; } /** * Read an uncompressed SGI image. * @param out_buf output buffer * @param out_end end ofoutput buffer * @param s the current image state * @return 0 if read success, otherwise return -1. */ static int read_uncompressed_sgi(unsigned char* out_buf, uint8_t* out_end, SgiState *s) { int x, y, z; unsigned int offset = s->height * s->width * s->bytes_per_channel; GetByteContext gp[4]; /* Test buffer size. */ if (offset * s->depth > bytestream2_get_bytes_left(&s->g)) return AVERROR_INVALIDDATA; /* Create a reader for each plane */ for (z = 0; z < s->depth; z++) { gp[z] = s->g; bytestream2_skip(&gp[z], z * offset); } for (y = s->height - 1; y >= 0; y--) { out_end = out_buf + (y * s->linesize); if (s->bytes_per_channel == 1) { for (x = s->width; x > 0; x--) for (z = 0; z < s->depth; z++) *out_end++ = bytestream2_get_byteu(&gp[z]); } else { uint16_t *out16 = (uint16_t *)out_end; for (x = s->width; x > 0; x--) for (z = 0; z < s->depth; z++) *out16++ = bytestream2_get_ne16u(&gp[z]); } } return 0; } static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { SgiState *s = avctx->priv_data; AVFrame *picture = data; AVFrame *p = &s->picture; unsigned int dimension, rle; int ret = 0; uint8_t *out_buf, *out_end; bytestream2_init(&s->g, avpkt->data, avpkt->size); if (bytestream2_get_bytes_left(&s->g) < SGI_HEADER_SIZE) { av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size); return AVERROR_INVALIDDATA; } /* Test for SGI magic. */ if (bytestream2_get_be16(&s->g) != SGI_MAGIC) { av_log(avctx, AV_LOG_ERROR, "bad magic number\n"); return AVERROR_INVALIDDATA; } rle = bytestream2_get_byte(&s->g); s->bytes_per_channel = bytestream2_get_byte(&s->g); dimension = bytestream2_get_be16(&s->g); s->width = bytestream2_get_be16(&s->g); s->height = bytestream2_get_be16(&s->g); s->depth = bytestream2_get_be16(&s->g); if (s->bytes_per_channel != 1 && (s->bytes_per_channel != 2 || rle)) { av_log(avctx, AV_LOG_ERROR, "wrong channel number\n"); return -1; } /* Check for supported image dimensions. */ if (dimension != 2 && dimension != 3) { av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n"); return -1; } if (s->depth == SGI_GRAYSCALE) { avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_GRAY16BE : PIX_FMT_GRAY8; } else if (s->depth == SGI_RGB) { avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGB48BE : PIX_FMT_RGB24; } else if (s->depth == SGI_RGBA) { avctx->pix_fmt = s->bytes_per_channel == 2 ? PIX_FMT_RGBA64BE : PIX_FMT_RGBA; } else { av_log(avctx, AV_LOG_ERROR, "wrong picture format\n"); return -1; } if (av_image_check_size(s->width, s->height, 0, avctx)) return -1; avcodec_set_dimensions(avctx, s->width, s->height); if (p->data[0]) avctx->release_buffer(avctx, p); 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 = AV_PICTURE_TYPE_I; p->key_frame = 1; out_buf = p->data[0]; out_end = out_buf + p->linesize[0] * s->height; s->linesize = p->linesize[0]; /* Skip header. */ bytestream2_seek(&s->g, SGI_HEADER_SIZE, SEEK_SET); if (rle) { ret = read_rle_sgi(out_end, s); } else { ret = read_uncompressed_sgi(out_buf, out_end, s); } if (ret == 0) { *picture = s->picture; *data_size = sizeof(AVPicture); return avpkt->size; } else { return ret; } } static av_cold int sgi_init(AVCodecContext *avctx){ SgiState *s = avctx->priv_data; avcodec_get_frame_defaults(&s->picture); avctx->coded_frame = &s->picture; return 0; } static av_cold int sgi_end(AVCodecContext *avctx) { SgiState * const s = avctx->priv_data; if (s->picture.data[0]) avctx->release_buffer(avctx, &s->picture); return 0; } AVCodec ff_sgi_decoder = { .name = "sgi", .type = AVMEDIA_TYPE_VIDEO, .id = CODEC_ID_SGI, .priv_data_size = sizeof(SgiState), .init = sgi_init, .close = sgi_end, .decode = decode_frame, .long_name = NULL_IF_CONFIG_SMALL("SGI image"), };