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/*
* Bethesda VID video decoder
* Copyright (C) 2007 Nicholas Tung
*
* 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 bethsoftvideo.c
* @brief Bethesda Softworks VID Video Decoder
* @author Nicholas Tung [ntung (at. ntung com] (2007-03)
* @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
* @sa http://www.svatopluk.com/andux/docs/dfvid.html
*/
#include "common.h"
#include "dsputil.h"
#include "bethsoftvideo.h"
#include "bytestream.h"
typedef struct BethsoftvidContext {
AVFrame frame;
} BethsoftvidContext;
static int bethsoftvid_decode_init(AVCodecContext *avctx)
{
BethsoftvidContext *vid = avctx->priv_data;
vid->frame.reference = 1;
vid->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
avctx->pix_fmt = PIX_FMT_PAL8; // palette in vid->frame.data[1]
av_log(avctx, AV_LOG_DEBUG, "[bethsoftvid video decoder] init\n");
return 0;
}
static void set_palette(AVFrame * frame, uint8_t * palette_buffer)
{
uint32_t * palette = (uint32_t *)frame->data[1];
int a;
for(a = 0; a < VID_PALETTE_NUMCOLORS; a++)
{
palette[a] = AV_RB24(&palette_buffer[a * 3]) * 4; // multiply all colors by 4
}
frame->palette_has_changed = 1;
}
static int bethsoftvid_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
BethsoftvidContext * vid = avctx->priv_data;
char block_type;
uint8_t * destination;
uint8_t * frame_end;
int line_remaining = avctx->width; // number of bytes remaining on a line
const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
uint8_t rle_num_bytes;
int yoffset;
av_log(avctx, AV_LOG_DEBUG, "[bethsoftvid video decoder] decoding frame\n");
// reget buffer will copy old data, good for simple difference frames
if (avctx->reget_buffer(avctx, &vid->frame)) {
av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
return -1;
}
destination = vid->frame.data[0];
frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
switch(block_type = *buf++)
{
case PALETTE_BLOCK: set_palette(&vid->frame, buf); return 0;
case VIDEO_YOFFSET_DIFFERENCE_FRAME_BLOCK:
yoffset = bytestream_get_le16(&buf);
if(yoffset >= avctx->height) { return -1; }
destination += vid->frame.linesize[0] * yoffset;
}
// main code
while((rle_num_bytes = *buf++))
{
int length = rle_num_bytes & 0x7f;
// copy any bytes starting at the current position, and ending at the frame width
while(length > line_remaining)
{
if(rle_num_bytes < 0x80) { bytestream_get_buffer(&buf, destination, line_remaining); }
else if(block_type == VIDEO_FULL_FRAME_BLOCK) { memset(destination, buf[0], line_remaining); }
length -= line_remaining; // decrement the number of bytes to be copied
destination += line_remaining + wrap_to_next_line; // skip over extra bytes at end of frame
line_remaining = avctx->width;
if(destination == frame_end) { goto end; }
}
// copy any remaining bytes after / if line overflows
if(rle_num_bytes < 0x80) { bytestream_get_buffer(&buf, destination, length); }
else if(block_type == VIDEO_FULL_FRAME_BLOCK) { memset(destination, *buf++, length); }
line_remaining -= length;
destination += length;
}
end:
*data_size = sizeof(AVFrame);
*(AVFrame*)data = vid->frame;
return buf_size;
}
static int bethsoftvid_decode_end(AVCodecContext *avctx)
{
BethsoftvidContext * vid = avctx->priv_data;
av_log(avctx, AV_LOG_DEBUG, "[bethsoftvid video decoder] closing\n");
if(vid->frame.data[0]) { avctx->release_buffer(avctx, &vid->frame); }
return 0;
}
AVCodec bethsoftvid_decoder = {
.name = "bethsoftvid",
.type = CODEC_TYPE_VIDEO,
.id = CODEC_ID_BETHSOFTVID,
.priv_data_size = sizeof(BethsoftvidContext),
.init = bethsoftvid_decode_init,
.close = bethsoftvid_decode_end,
.decode = bethsoftvid_decode_frame,
};
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