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def97856de
Express bitfields more simply. Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
229 lines
6.4 KiB
C
229 lines
6.4 KiB
C
/*
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* RL2 Video Decoder
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* Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de)
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* RL2 Video Decoder
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* @author Sascha Sommer (saschasommer@freenet.de)
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* @see http://wiki.multimedia.cx/index.php?title=RL2
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "libavutil/internal.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/mem.h"
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#include "avcodec.h"
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#include "internal.h"
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#define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
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typedef struct Rl2Context {
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AVCodecContext *avctx;
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uint16_t video_base; ///< initial drawing offset
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uint32_t clr_count; ///< number of used colors (currently unused)
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uint8_t *back_frame; ///< background frame
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uint32_t palette[AVPALETTE_COUNT];
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} Rl2Context;
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/**
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* Run Length Decode a single 320x200 frame
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* @param s rl2 context
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* @param in input buffer
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* @param size input buffer size
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* @param out ouput buffer
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* @param stride stride of the output buffer
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* @param video_base offset of the rle data inside the frame
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*/
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static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size,
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uint8_t *out, int stride, int video_base)
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{
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int base_x = video_base % s->avctx->width;
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int base_y = video_base / s->avctx->width;
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int stride_adj = stride - s->avctx->width;
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int i;
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const uint8_t *back_frame = s->back_frame;
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const uint8_t *in_end = in + size;
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const uint8_t *out_end = out + stride * s->avctx->height;
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uint8_t *line_end;
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/** copy start of the background frame */
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for (i = 0; i <= base_y; i++) {
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if (s->back_frame)
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memcpy(out, back_frame, s->avctx->width);
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out += stride;
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back_frame += s->avctx->width;
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}
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back_frame += base_x - s->avctx->width;
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line_end = out - stride_adj;
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out += base_x - stride;
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/** decode the variable part of the frame */
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while (in < in_end) {
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uint8_t val = *in++;
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int len = 1;
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if (val >= 0x80) {
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if (in >= in_end)
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break;
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len = *in++;
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if (!len)
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break;
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}
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if (len >= out_end - out)
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break;
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if (s->back_frame)
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val |= 0x80;
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else
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val &= ~0x80;
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while (len--) {
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*out++ = (val == 0x80) ? *back_frame : val;
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back_frame++;
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if (out == line_end) {
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out += stride_adj;
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line_end += stride;
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if (len >= out_end - out)
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break;
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}
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}
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}
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/** copy the rest from the background frame */
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if (s->back_frame) {
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while (out < out_end) {
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memcpy(out, back_frame, line_end - out);
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back_frame += line_end - out;
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out = line_end + stride_adj;
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line_end += stride;
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}
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}
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}
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/**
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* Initialize the decoder
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* @param avctx decoder context
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* @return 0 success, -1 on error
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*/
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static av_cold int rl2_decode_init(AVCodecContext *avctx)
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{
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Rl2Context *s = avctx->priv_data;
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int back_size;
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int i;
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s->avctx = avctx;
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avctx->pix_fmt = AV_PIX_FMT_PAL8;
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/** parse extra data */
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if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) {
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av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
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return AVERROR(EINVAL);
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}
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/** get frame_offset */
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s->video_base = AV_RL16(&avctx->extradata[0]);
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s->clr_count = AV_RL32(&avctx->extradata[2]);
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if (s->video_base >= avctx->width * avctx->height) {
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av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
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return AVERROR_INVALIDDATA;
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}
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/** initialize palette */
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for (i = 0; i < AVPALETTE_COUNT; i++)
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s->palette[i] = AV_RB24(&avctx->extradata[6 + i * 3]);
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/** decode background frame if present */
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back_size = avctx->extradata_size - EXTRADATA1_SIZE;
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if (back_size > 0) {
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uint8_t *back_frame = av_mallocz(avctx->width*avctx->height);
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if (!back_frame)
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return AVERROR(ENOMEM);
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rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size,
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back_frame, avctx->width, 0);
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s->back_frame = back_frame;
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}
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return 0;
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}
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static int rl2_decode_frame(AVCodecContext *avctx,
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void *data, int *got_frame,
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AVPacket *avpkt)
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{
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AVFrame *frame = data;
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const uint8_t *buf = avpkt->data;
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int ret, buf_size = avpkt->size;
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Rl2Context *s = avctx->priv_data;
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
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av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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return ret;
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}
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/** run length decode */
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rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0],
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s->video_base);
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/** make the palette available on the way out */
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memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
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*got_frame = 1;
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/** report that the buffer was completely consumed */
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return buf_size;
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}
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/**
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* Uninit decoder
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* @param avctx decoder context
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* @return 0 success, -1 on error
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*/
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static av_cold int rl2_decode_end(AVCodecContext *avctx)
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{
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Rl2Context *s = avctx->priv_data;
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av_free(s->back_frame);
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return 0;
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}
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AVCodec ff_rl2_decoder = {
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.name = "rl2",
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.long_name = NULL_IF_CONFIG_SMALL("RL2 video"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_RL2,
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.priv_data_size = sizeof(Rl2Context),
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.init = rl2_decode_init,
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.close = rl2_decode_end,
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.decode = rl2_decode_frame,
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.capabilities = AV_CODEC_CAP_DR1,
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};
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