/* * Tiertex Limited SEQ Video Decoder * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.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 */ /** * @file * Tiertex Limited SEQ video decoder */ #define BITSTREAM_READER_LE #include "avcodec.h" #include "get_bits.h" #include "internal.h" typedef struct SeqVideoContext { AVCodecContext *avctx; AVFrame *frame; } SeqVideoContext; static const unsigned char *seq_unpack_rle_block(const unsigned char *src, const unsigned char *src_end, unsigned char *dst, int dst_size) { int i, len, sz; GetBitContext gb; int code_table[64]; /* get the rle codes */ init_get_bits(&gb, src, (src_end - src) * 8); for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) { if (get_bits_left(&gb) < 4) return NULL; code_table[i] = get_sbits(&gb, 4); sz += FFABS(code_table[i]); } src += (get_bits_count(&gb) + 7) / 8; /* do the rle unpacking */ for (i = 0; i < 64 && dst_size > 0; i++) { len = code_table[i]; if (len < 0) { len = -len; if (src_end - src < 1) return NULL; memset(dst, *src++, FFMIN(len, dst_size)); } else { if (src_end - src < len) return NULL; memcpy(dst, src, FFMIN(len, dst_size)); src += len; } dst += len; dst_size -= len; } return src; } static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned char *src, const unsigned char *src_end, unsigned char *dst) { const unsigned char *color_table; int b, i, len, bits; GetBitContext gb; unsigned char block[8 * 8]; if (src_end - src < 1) return NULL; len = *src++; if (len & 0x80) { switch (len & 3) { case 1: src = seq_unpack_rle_block(src, src_end, block, sizeof(block)); for (b = 0; b < 8; b++) { memcpy(dst, &block[b * 8], 8); dst += seq->frame->linesize[0]; } break; case 2: src = seq_unpack_rle_block(src, src_end, block, sizeof(block)); for (i = 0; i < 8; i++) { for (b = 0; b < 8; b++) dst[b * seq->frame->linesize[0]] = block[i * 8 + b]; ++dst; } break; } } else { if (len <= 0) return NULL; bits = ff_log2_tab[len - 1] + 1; if (src_end - src < len + 8 * bits) return NULL; color_table = src; src += len; init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8; for (b = 0; b < 8; b++) { for (i = 0; i < 8; i++) dst[i] = color_table[get_bits(&gb, bits)]; dst += seq->frame->linesize[0]; } } return src; } static const unsigned char *seq_decode_op2(SeqVideoContext *seq, const unsigned char *src, const unsigned char *src_end, unsigned char *dst) { int i; if (src_end - src < 8 * 8) return NULL; for (i = 0; i < 8; i++) { memcpy(dst, src, 8); src += 8; dst += seq->frame->linesize[0]; } return src; } static const unsigned char *seq_decode_op3(SeqVideoContext *seq, const unsigned char *src, const unsigned char *src_end, unsigned char *dst) { int pos, offset; do { if (src_end - src < 2) return NULL; pos = *src++; offset = ((pos >> 3) & 7) * seq->frame->linesize[0] + (pos & 7); dst[offset] = *src++; } while (!(pos & 0x80)); return src; } static int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size) { const unsigned char *data_end = data + data_size; GetBitContext gb; int flags, i, j, x, y, op; unsigned char c[3]; unsigned char *dst; uint32_t *palette; flags = *data++; if (flags & 1) { palette = (uint32_t *)seq->frame->data[1]; if (data_end - data < 256 * 3) return AVERROR_INVALIDDATA; for (i = 0; i < 256; i++) { for (j = 0; j < 3; j++, data++) c[j] = (*data << 2) | (*data >> 4); palette[i] = 0xFFU << 24 | AV_RB24(c); } seq->frame->palette_has_changed = 1; } if (flags & 2) { if (data_end - data < 128) return AVERROR_INVALIDDATA; init_get_bits(&gb, data, 128 * 8); data += 128; for (y = 0; y < 128; y += 8) for (x = 0; x < 256; x += 8) { dst = &seq->frame->data[0][y * seq->frame->linesize[0] + x]; op = get_bits(&gb, 2); switch (op) { case 1: data = seq_decode_op1(seq, data, data_end, dst); break; case 2: data = seq_decode_op2(seq, data, data_end, dst); break; case 3: data = seq_decode_op3(seq, data, data_end, dst); break; } if (!data) return AVERROR_INVALIDDATA; } } return 0; } static av_cold int seqvideo_decode_init(AVCodecContext *avctx) { SeqVideoContext *seq = avctx->priv_data; int ret; seq->avctx = avctx; avctx->pix_fmt = AV_PIX_FMT_PAL8; ret = ff_set_dimensions(avctx, 256, 128); if (ret < 0) return ret; seq->frame = av_frame_alloc(); if (!seq->frame) return AVERROR(ENOMEM); return 0; } static int seqvideo_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; int ret; SeqVideoContext *seq = avctx->priv_data; if ((ret = ff_reget_buffer(avctx, seq->frame, 0)) < 0) return ret; if (seqvideo_decode(seq, buf, buf_size)) return AVERROR_INVALIDDATA; if ((ret = av_frame_ref(data, seq->frame)) < 0) return ret; *got_frame = 1; return buf_size; } static av_cold int seqvideo_decode_end(AVCodecContext *avctx) { SeqVideoContext *seq = avctx->priv_data; av_frame_free(&seq->frame); return 0; } AVCodec ff_tiertexseqvideo_decoder = { .name = "tiertexseqvideo", .long_name = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_TIERTEXSEQVIDEO, .priv_data_size = sizeof(SeqVideoContext), .init = seqvideo_decode_init, .close = seqvideo_decode_end, .decode = seqvideo_decode_frame, .capabilities = AV_CODEC_CAP_DR1, };