From 2fc85fe96e7e0e5fc433b98eacebf4d3511d2d58 Mon Sep 17 00:00:00 2001 From: Nidhi Makhijani Date: Sun, 6 Jul 2014 19:33:49 +0530 Subject: bmv: Split audio and video decoder Signed-off-by: Diego Biurrun --- libavcodec/bmvvideo.c | 293 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 293 insertions(+) create mode 100644 libavcodec/bmvvideo.c (limited to 'libavcodec/bmvvideo.c') diff --git a/libavcodec/bmvvideo.c b/libavcodec/bmvvideo.c new file mode 100644 index 0000000000..ebc8e7a082 --- /dev/null +++ b/libavcodec/bmvvideo.c @@ -0,0 +1,293 @@ +/* + * Discworld II BMV video decoder + * Copyright (c) 2011 Konstantin Shishkov + * + * This file is part of Libav. + * + * Libav 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. + * + * Libav 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 Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libavutil/common.h" + +#include "avcodec.h" +#include "bytestream.h" +#include "internal.h" + +enum BMVFlags{ + BMV_NOP = 0, + BMV_END, + BMV_DELTA, + BMV_INTRA, + + BMV_SCROLL = 0x04, + BMV_PALETTE = 0x08, + BMV_COMMAND = 0x10, + BMV_AUDIO = 0x20, + BMV_EXT = 0x40, + BMV_PRINT = 0x80 +}; + +#define SCREEN_WIDE 640 +#define SCREEN_HIGH 429 + +typedef struct BMVDecContext { + AVCodecContext *avctx; + + uint8_t *frame, frame_base[SCREEN_WIDE * (SCREEN_HIGH + 1)]; + uint32_t pal[256]; + const uint8_t *stream; +} BMVDecContext; + +#define NEXT_BYTE(v) v = forward ? v + 1 : v - 1; + +static int decode_bmv_frame(const uint8_t *source, int src_len, uint8_t *frame, int frame_off) +{ + unsigned val, saved_val = 0; + int tmplen = src_len; + const uint8_t *src, *source_end = source + src_len; + uint8_t *frame_end = frame + SCREEN_WIDE * SCREEN_HIGH; + uint8_t *dst, *dst_end; + int len, mask; + int forward = (frame_off <= -SCREEN_WIDE) || (frame_off >= 0); + int read_two_nibbles, flag; + int advance_mode; + int mode = 0; + int i; + + if (src_len <= 0) + return AVERROR_INVALIDDATA; + + if (forward) { + src = source; + dst = frame; + dst_end = frame_end; + } else { + src = source + src_len - 1; + dst = frame_end - 1; + dst_end = frame - 1; + } + for (;;) { + int shift = 0; + flag = 0; + + /* The mode/len decoding is a bit strange: + * values are coded as variable-length codes with nibble units, + * code end is signalled by two top bits in the nibble being nonzero. + * And since data is bytepacked and we read two nibbles at a time, + * we may get a nibble belonging to the next code. + * Hence this convoluted loop. + */ + if (!mode || (tmplen == 4)) { + if (src < source || src >= source_end) + return AVERROR_INVALIDDATA; + val = *src; + read_two_nibbles = 1; + } else { + val = saved_val; + read_two_nibbles = 0; + } + if (!(val & 0xC)) { + for (;;) { + if (!read_two_nibbles) { + if (src < source || src >= source_end) + return AVERROR_INVALIDDATA; + shift += 2; + val |= *src << shift; + if (*src & 0xC) + break; + } + // two upper bits of the nibble is zero, + // so shift top nibble value down into their place + read_two_nibbles = 0; + shift += 2; + mask = (1 << shift) - 1; + val = ((val >> 2) & ~mask) | (val & mask); + NEXT_BYTE(src); + if ((val & (0xC << shift))) { + flag = 1; + break; + } + } + } else if (mode) { + flag = tmplen != 4; + } + if (flag) { + tmplen = 4; + } else { + saved_val = val >> (4 + shift); + tmplen = 0; + val &= (1 << (shift + 4)) - 1; + NEXT_BYTE(src); + } + advance_mode = val & 1; + len = (val >> 1) - 1; + mode += 1 + advance_mode; + if (mode >= 4) + mode -= 3; + if (len <= 0 || FFABS(dst_end - dst) < len) + return AVERROR_INVALIDDATA; + switch (mode) { + case 1: + if (forward) { + if (dst - frame + SCREEN_WIDE < frame_off || + dst - frame + SCREEN_WIDE + frame_off < 0 || + frame_end - dst < frame_off + len || + frame_end - dst < len) + return AVERROR_INVALIDDATA; + for (i = 0; i < len; i++) + dst[i] = dst[frame_off + i]; + dst += len; + } else { + dst -= len; + if (dst - frame + SCREEN_WIDE < frame_off || + dst - frame + SCREEN_WIDE + frame_off < 0 || + frame_end - dst < frame_off + len || + frame_end - dst < len) + return AVERROR_INVALIDDATA; + for (i = len - 1; i >= 0; i--) + dst[i] = dst[frame_off + i]; + } + break; + case 2: + if (forward) { + if (source + src_len - src < len) + return AVERROR_INVALIDDATA; + memcpy(dst, src, len); + dst += len; + src += len; + } else { + if (src - source < len) + return AVERROR_INVALIDDATA; + dst -= len; + src -= len; + memcpy(dst, src, len); + } + break; + case 3: + val = forward ? dst[-1] : dst[1]; + if (forward) { + memset(dst, val, len); + dst += len; + } else { + dst -= len; + memset(dst, val, len); + } + break; + default: + break; + } + if (dst == dst_end) + return 0; + } + return 0; +} + +static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, + AVPacket *pkt) +{ + BMVDecContext * const c = avctx->priv_data; + AVFrame *frame = data; + int type, scr_off; + int i, ret; + uint8_t *srcptr, *outptr; + + c->stream = pkt->data; + type = bytestream_get_byte(&c->stream); + if (type & BMV_AUDIO) { + int blobs = bytestream_get_byte(&c->stream); + if (pkt->size < blobs * 65 + 2) { + av_log(avctx, AV_LOG_ERROR, "Audio data doesn't fit in frame\n"); + return AVERROR_INVALIDDATA; + } + c->stream += blobs * 65; + } + if (type & BMV_COMMAND) { + int command_size = (type & BMV_PRINT) ? 8 : 10; + if (c->stream - pkt->data + command_size > pkt->size) { + av_log(avctx, AV_LOG_ERROR, "Command data doesn't fit in frame\n"); + return AVERROR_INVALIDDATA; + } + c->stream += command_size; + } + if (type & BMV_PALETTE) { + if (c->stream - pkt->data > pkt->size - 768) { + av_log(avctx, AV_LOG_ERROR, "Palette data doesn't fit in frame\n"); + return AVERROR_INVALIDDATA; + } + for (i = 0; i < 256; i++) + c->pal[i] = bytestream_get_be24(&c->stream); + } + if (type & BMV_SCROLL) { + if (c->stream - pkt->data > pkt->size - 2) { + av_log(avctx, AV_LOG_ERROR, "Screen offset data doesn't fit in frame\n"); + return AVERROR_INVALIDDATA; + } + scr_off = (int16_t)bytestream_get_le16(&c->stream); + } else if ((type & BMV_INTRA) == BMV_INTRA) { + scr_off = -640; + } else { + scr_off = 0; + } + + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) { + av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); + return ret; + } + + if (decode_bmv_frame(c->stream, pkt->size - (c->stream - pkt->data), c->frame, scr_off)) { + av_log(avctx, AV_LOG_ERROR, "Error decoding frame data\n"); + return AVERROR_INVALIDDATA; + } + + memcpy(frame->data[1], c->pal, AVPALETTE_SIZE); + frame->palette_has_changed = type & BMV_PALETTE; + + outptr = frame->data[0]; + srcptr = c->frame; + + for (i = 0; i < avctx->height; i++) { + memcpy(outptr, srcptr, avctx->width); + srcptr += avctx->width; + outptr += frame->linesize[0]; + } + + *got_frame = 1; + + /* always report that the buffer was completely consumed */ + return pkt->size; +} + +static av_cold int decode_init(AVCodecContext *avctx) +{ + BMVDecContext * const c = avctx->priv_data; + + c->avctx = avctx; + avctx->pix_fmt = AV_PIX_FMT_PAL8; + + c->frame = c->frame_base + 640; + + return 0; +} + +AVCodec ff_bmv_video_decoder = { + .name = "bmv_video", + .long_name = NULL_IF_CONFIG_SMALL("Discworld II BMV video"), + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_BMV_VIDEO, + .priv_data_size = sizeof(BMVDecContext), + .init = decode_init, + .decode = decode_frame, + .capabilities = CODEC_CAP_DR1, +}; -- cgit v1.2.3