mirror of
https://github.com/FFmpeg/FFmpeg.git
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278 lines
8.6 KiB
C
278 lines
8.6 KiB
C
/*
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* SGI image decoder
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* Todd Kirby <doubleshot@pacbell.net>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "bytestream.h"
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#include "codec_internal.h"
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#include "decode.h"
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#include "sgi.h"
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/**
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* Expand an RLE row into a channel.
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* @param logctx a logcontext
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* @param out_buf Points to one line after the output buffer.
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* @param g GetByteContext used to read input from
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* @param width length of out_buf in nb of elements
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* @return nb of elements written, else return error code.
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*/
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static int expand_rle_row8(void *logctx, uint8_t *out_buf,
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GetByteContext *g, unsigned width)
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{
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unsigned char pixel, count;
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unsigned char *orig = out_buf;
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uint8_t *out_end = out_buf + width;
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while (out_buf < out_end) {
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if (bytestream2_get_bytes_left(g) < 1)
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return AVERROR_INVALIDDATA;
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pixel = bytestream2_get_byteu(g);
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if (!(count = (pixel & 0x7f))) {
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break;
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}
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/* Check for buffer overflow. */
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if (out_end - out_buf < count) {
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av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
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return AVERROR_INVALIDDATA;
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}
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if (pixel & 0x80) {
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while (count--)
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*out_buf++ = bytestream2_get_byte(g);
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} else {
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pixel = bytestream2_get_byte(g);
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while (count--)
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*out_buf++ = pixel;
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}
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}
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return out_buf - orig;
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}
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static int expand_rle_row16(void *logctx, uint16_t *out_buf,
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GetByteContext *g, unsigned width)
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{
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unsigned short pixel;
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unsigned char count;
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unsigned short *orig = out_buf;
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uint16_t *out_end = out_buf + width;
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while (out_buf < out_end) {
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if (bytestream2_get_bytes_left(g) < 2)
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return AVERROR_INVALIDDATA;
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pixel = bytestream2_get_be16u(g);
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if (!(count = (pixel & 0x7f)))
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break;
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/* Check for buffer overflow. */
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if (out_end - out_buf < count) {
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av_log(logctx, AV_LOG_ERROR, "Invalid pixel count.\n");
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return AVERROR_INVALIDDATA;
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}
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if (pixel & 0x80) {
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while (count--) {
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pixel = bytestream2_get_ne16(g);
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AV_WN16A(out_buf, pixel);
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out_buf++;
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}
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} else {
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pixel = bytestream2_get_ne16(g);
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while (count--) {
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AV_WN16A(out_buf, pixel);
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out_buf++;
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}
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}
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}
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return out_buf - orig;
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}
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/**
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* Read a run length encoded SGI image.
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* @param out_buf output buffer
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* @param s the current image state
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* @return 0 if no error, else return error code.
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*/
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static int read_rle_sgi(void *logctx, uint8_t *out[4], ptrdiff_t stride[4],
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GetByteContext *g, unsigned width, int height,
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unsigned nb_components, unsigned bytes_per_channel)
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{
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unsigned int len = height * nb_components * 4;
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GetByteContext g_table = *g;
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unsigned int start_offset;
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int ret;
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/* size of RLE offset and length tables */
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if (len * 2 > bytestream2_get_bytes_left(g)) {
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return AVERROR_INVALIDDATA;
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}
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for (unsigned z = 0; z < nb_components; z++) {
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uint8_t *dest_row = out[z] + (height - 1) * stride[z];
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while (1) {
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start_offset = bytestream2_get_be32(&g_table);
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bytestream2_seek(g, start_offset, SEEK_SET);
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if (bytes_per_channel == 1)
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ret = expand_rle_row8(logctx, dest_row, g, width);
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else
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ret = expand_rle_row16(logctx, (uint16_t *)dest_row, g, width);
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if (ret != width)
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return AVERROR_INVALIDDATA;
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if (dest_row == out[z])
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break;
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dest_row -= stride[z];
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}
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}
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return 0;
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}
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/**
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* Read an uncompressed SGI image.
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* @param out_buf output buffer
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* @param s the current image state
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* @return 0 if read success, else return error code.
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*/
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static int read_uncompressed_sgi(uint8_t *const out[4], const ptrdiff_t stride[4],
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GetByteContext *g, unsigned width, int height,
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unsigned nb_components, unsigned bytes_per_channel)
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{
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unsigned rowsize = width * bytes_per_channel;
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/* Test buffer size. */
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if (rowsize * (int64_t)height * nb_components > bytestream2_get_bytes_left(g))
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return AVERROR_INVALIDDATA;
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for (unsigned z = 0; z < nb_components; z++) {
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uint8_t *cur_row = out[z] + (height - 1) * stride[z];
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while (1) {
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bytestream2_get_bufferu(g, cur_row, rowsize);
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if (cur_row == out[z])
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break;
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cur_row -= stride[z];
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}
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}
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return 0;
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}
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static int decode_frame(AVCodecContext *avctx, AVFrame *p,
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int *got_frame, AVPacket *avpkt)
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{
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GetByteContext g;
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unsigned int bytes_per_channel, nb_components, dimension, rle, width;
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uint8_t *out[4];
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ptrdiff_t linesize[4];
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int height;
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int ret = 0;
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bytestream2_init(&g, avpkt->data, avpkt->size);
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if (bytestream2_get_bytes_left(&g) < SGI_HEADER_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "buf_size too small (%d)\n", avpkt->size);
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return AVERROR_INVALIDDATA;
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}
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/* Test for SGI magic. */
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if (bytestream2_get_be16u(&g) != SGI_MAGIC) {
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av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
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return AVERROR_INVALIDDATA;
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}
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rle = bytestream2_get_byteu(&g);
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bytes_per_channel = bytestream2_get_byteu(&g);
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dimension = bytestream2_get_be16u(&g);
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width = bytestream2_get_be16u(&g);
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height = bytestream2_get_be16u(&g);
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nb_components = bytestream2_get_be16u(&g);
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if (bytes_per_channel != 1 && bytes_per_channel != 2) {
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av_log(avctx, AV_LOG_ERROR, "wrong channel number\n");
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return AVERROR_INVALIDDATA;
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}
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/* Check for supported image dimensions. */
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if (dimension != 2 && dimension != 3) {
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av_log(avctx, AV_LOG_ERROR, "wrong dimension number\n");
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return AVERROR_INVALIDDATA;
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}
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if (nb_components == SGI_GRAYSCALE) {
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avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GRAY16BE : AV_PIX_FMT_GRAY8;
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} else if (nb_components == SGI_RGB) {
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avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRP16BE : AV_PIX_FMT_GBRP;
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} else if (nb_components == SGI_RGBA) {
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avctx->pix_fmt = bytes_per_channel == 2 ? AV_PIX_FMT_GBRAP16BE : AV_PIX_FMT_GBRAP;
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} else {
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av_log(avctx, AV_LOG_ERROR, "wrong picture format\n");
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return AVERROR_INVALIDDATA;
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}
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ret = ff_set_dimensions(avctx, width, height);
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if (ret < 0)
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return ret;
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if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
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return ret;
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switch (nb_components) {
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#define MAP(in_idx, out_idx) \
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out[(in_idx)] = p->data[(out_idx)]; \
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linesize[(in_idx)] = p->linesize[(out_idx)]
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case SGI_GRAYSCALE:
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MAP(0, 0);
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break;
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case SGI_RGBA:
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MAP(3, 3);
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/* fallthrough */
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case SGI_RGB:
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MAP(0, 2);
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MAP(1, 0);
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MAP(2, 1);
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break;
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}
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p->pict_type = AV_PICTURE_TYPE_I;
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p->flags |= AV_FRAME_FLAG_KEY;
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/* Skip header. */
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bytestream2_seek(&g, SGI_HEADER_SIZE, SEEK_SET);
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if (rle) {
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ret = read_rle_sgi(avctx, out, linesize, &g,
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width, height, nb_components, bytes_per_channel);
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} else {
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ret = read_uncompressed_sgi(out, linesize, &g,
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width, height, nb_components, bytes_per_channel);
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}
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if (ret)
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return ret;
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*got_frame = 1;
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return avpkt->size;
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}
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const FFCodec ff_sgi_decoder = {
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.p.name = "sgi",
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CODEC_LONG_NAME("SGI image"),
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.p.type = AVMEDIA_TYPE_VIDEO,
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.p.id = AV_CODEC_ID_SGI,
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FF_CODEC_DECODE_CB(decode_frame),
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.p.capabilities = AV_CODEC_CAP_DR1,
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};
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