FFmpeg/libavcodec/rl2.c
Thilo Borgmann bd7d08e27e Remove incomplete Doxygen for static decode_frame functions.
These functions are not documented for other decoders and
should be obvious enough even without Doxygen.
patch by Thilo Borgmann, thilo.borgmann googlemail com

Originally committed as revision 24237 to svn://svn.ffmpeg.org/ffmpeg/trunk
2010-07-14 13:12:24 +00:00

235 lines
6.3 KiB
C

/*
* RL2 Video Decoder
* Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de)
*
* 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
*/
/**
* RL2 Video Decoder
* @file
* @author Sascha Sommer (saschasommer@freenet.de)
* For more information about the RL2 format, visit:
* http://wiki.multimedia.cx/index.php?title=RL2
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
typedef struct Rl2Context {
AVCodecContext *avctx;
AVFrame frame;
unsigned short video_base; ///< initial drawing offset
unsigned int clr_count; ///< number of used colors (currently unused)
unsigned char* back_frame; ///< background frame
unsigned int palette[AVPALETTE_COUNT];
} Rl2Context;
/**
* Run Length Decode a single 320x200 frame
* @param s rl2 context
* @param in input buffer
* @param size input buffer size
* @param out ouput buffer
* @param stride stride of the output buffer
* @param video_base offset of the rle data inside the frame
*/
static void rl2_rle_decode(Rl2Context *s,const unsigned char* in,int size,
unsigned char* out,int stride,int video_base){
int base_x = video_base % s->avctx->width;
int base_y = video_base / s->avctx->width;
int stride_adj = stride - s->avctx->width;
int i;
const unsigned char* back_frame = s->back_frame;
const unsigned char* in_end = in + size;
const unsigned char* out_end = out + stride * s->avctx->height;
unsigned char* line_end = out + s->avctx->width;
/** copy start of the background frame */
for(i=0;i<=base_y;i++){
if(s->back_frame)
memcpy(out,back_frame,s->avctx->width);
out += stride;
back_frame += s->avctx->width;
}
back_frame += base_x - s->avctx->width;
line_end = out - stride_adj;
out += base_x - stride;
/** decode the variable part of the frame */
while(in < in_end){
unsigned char val = *in++;
int len = 1;
if(val >= 0x80){
if(in >= in_end)
break;
len = *in++;
if(!len)
break;
}
if(len >= out_end - out)
break;
if(s->back_frame)
val |= 0x80;
else
val &= ~0x80;
while(len--){
*out++ = (val == 0x80)? *back_frame:val;
back_frame++;
if(out == line_end){
out += stride_adj;
line_end += stride;
if(len >= out_end - out)
break;
}
}
}
/** copy the rest from the background frame */
if(s->back_frame){
while(out < out_end){
memcpy(out, back_frame, line_end - out);
back_frame += line_end - out;
out = line_end + stride_adj;
line_end += stride;
}
}
}
/**
* Initialize the decoder
* @param avctx decoder context
* @return 0 success, -1 on error
*/
static av_cold int rl2_decode_init(AVCodecContext *avctx)
{
Rl2Context *s = avctx->priv_data;
int back_size;
int i;
s->avctx = avctx;
avctx->pix_fmt = PIX_FMT_PAL8;
/** parse extra data */
if(!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE){
av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
return -1;
}
/** get frame_offset */
s->video_base = AV_RL16(&avctx->extradata[0]);
s->clr_count = AV_RL32(&avctx->extradata[2]);
if(s->video_base >= avctx->width * avctx->height){
av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
return -1;
}
/** initialize palette */
for(i=0;i<AVPALETTE_COUNT;i++)
s->palette[i] = AV_RB24(&avctx->extradata[6 + i * 3]);
/** decode background frame if present */
back_size = avctx->extradata_size - EXTRADATA1_SIZE;
if(back_size > 0){
unsigned char* back_frame = av_mallocz(avctx->width*avctx->height);
if(!back_frame)
return -1;
rl2_rle_decode(s,avctx->extradata + EXTRADATA1_SIZE,back_size,
back_frame,avctx->width,0);
s->back_frame = back_frame;
}
return 0;
}
static int rl2_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
Rl2Context *s = avctx->priv_data;
if(s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
/** get buffer */
s->frame.reference= 0;
if(avctx->get_buffer(avctx, &s->frame)) {
av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
/** run length decode */
rl2_rle_decode(s,buf,buf_size,s->frame.data[0],s->frame.linesize[0],s->video_base);
/** make the palette available on the way out */
memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
/** report that the buffer was completely consumed */
return buf_size;
}
/**
* Uninit decoder
* @param avctx decoder context
* @return 0 success, -1 on error
*/
static av_cold int rl2_decode_end(AVCodecContext *avctx)
{
Rl2Context *s = avctx->priv_data;
if(s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
av_free(s->back_frame);
return 0;
}
AVCodec rl2_decoder = {
"rl2",
AVMEDIA_TYPE_VIDEO,
CODEC_ID_RL2,
sizeof(Rl2Context),
rl2_decode_init,
NULL,
rl2_decode_end,
rl2_decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("RL2 video"),
};