0,0 → 1,360 |
/* |
* Discworld II BMV video and audio decoder |
* Copyright (c) 2011 Konstantin Shishkov |
* |
* 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/avassert.h" |
#include "libavutil/channel_layout.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 |
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typedef struct BMVDecContext { |
AVCodecContext *avctx; |
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uint8_t *frame, frame_base[SCREEN_WIDE * (SCREEN_HIGH + 1)]; |
uint32_t pal[256]; |
const uint8_t *stream; |
} BMVDecContext; |
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#define NEXT_BYTE(v) v = forward ? v + 1 : v - 1; |
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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; |
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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(shift>22) |
return -1; |
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; |
av_assert0(len>0); |
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; |
} |
if (dst == dst_end) |
return 0; |
} |
return 0; |
} |
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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] = 0xFFU << 24 | 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; |
} |
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
return ret; |
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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; |
} |
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memcpy(frame->data[1], c->pal, AVPALETTE_SIZE); |
frame->palette_has_changed = type & BMV_PALETTE; |
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outptr = frame->data[0]; |
srcptr = c->frame; |
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for (i = 0; i < avctx->height; i++) { |
memcpy(outptr, srcptr, avctx->width); |
srcptr += avctx->width; |
outptr += frame->linesize[0]; |
} |
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*got_frame = 1; |
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/* always report that the buffer was completely consumed */ |
return pkt->size; |
} |
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static av_cold int decode_init(AVCodecContext *avctx) |
{ |
BMVDecContext * const c = avctx->priv_data; |
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c->avctx = avctx; |
avctx->pix_fmt = AV_PIX_FMT_PAL8; |
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if (avctx->width != SCREEN_WIDE || avctx->height != SCREEN_HIGH) { |
av_log(avctx, AV_LOG_ERROR, "Invalid dimension %dx%d\n", avctx->width, avctx->height); |
return AVERROR_INVALIDDATA; |
} |
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c->frame = c->frame_base + 640; |
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return 0; |
} |
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static const int bmv_aud_mults[16] = { |
16512, 8256, 4128, 2064, 1032, 516, 258, 192, 129, 88, 64, 56, 48, 40, 36, 32 |
}; |
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static av_cold int bmv_aud_decode_init(AVCodecContext *avctx) |
{ |
avctx->channels = 2; |
avctx->channel_layout = AV_CH_LAYOUT_STEREO; |
avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
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return 0; |
} |
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static int bmv_aud_decode_frame(AVCodecContext *avctx, void *data, |
int *got_frame_ptr, AVPacket *avpkt) |
{ |
AVFrame *frame = data; |
const uint8_t *buf = avpkt->data; |
int buf_size = avpkt->size; |
int blocks = 0, total_blocks, i; |
int ret; |
int16_t *output_samples; |
int scale[2]; |
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total_blocks = *buf++; |
if (buf_size < total_blocks * 65 + 1) { |
av_log(avctx, AV_LOG_ERROR, "expected %d bytes, got %d\n", |
total_blocks * 65 + 1, buf_size); |
return AVERROR_INVALIDDATA; |
} |
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/* get output buffer */ |
frame->nb_samples = total_blocks * 32; |
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
return ret; |
output_samples = (int16_t *)frame->data[0]; |
|
for (blocks = 0; blocks < total_blocks; blocks++) { |
uint8_t code = *buf++; |
code = (code >> 1) | (code << 7); |
scale[0] = bmv_aud_mults[code & 0xF]; |
scale[1] = bmv_aud_mults[code >> 4]; |
for (i = 0; i < 32; i++) { |
*output_samples++ = av_clip_int16((scale[0] * (int8_t)*buf++) >> 5); |
*output_samples++ = av_clip_int16((scale[1] * (int8_t)*buf++) >> 5); |
} |
} |
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*got_frame_ptr = 1; |
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return buf_size; |
} |
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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, |
}; |
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AVCodec ff_bmv_audio_decoder = { |
.name = "bmv_audio", |
.long_name = NULL_IF_CONFIG_SMALL("Discworld II BMV audio"), |
.type = AVMEDIA_TYPE_AUDIO, |
.id = AV_CODEC_ID_BMV_AUDIO, |
.init = bmv_aud_decode_init, |
.decode = bmv_aud_decode_frame, |
.capabilities = CODEC_CAP_DR1, |
}; |