mirror of
https://github.com/FFmpeg/FFmpeg.git
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6b892a4227
Originally committed as revision 4512 to svn://svn.ffmpeg.org/ffmpeg/trunk
189 lines
5.4 KiB
C
189 lines
5.4 KiB
C
/*
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*
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* Copyright (C) 2003 the ffmpeg project
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*
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* This library 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 of the License, or (at your option) any later version.
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*
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* This library 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 this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Creative YUV (CYUV) Video Decoder
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* by Mike Melanson (melanson@pcisys.net)
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* based on "Creative YUV (CYUV) stream format for AVI":
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* http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
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*
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*/
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/**
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* @file cyuv.c
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* Creative YUV (CYUV) Video Decoder.
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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 <unistd.h>
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#include "common.h"
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#include "avcodec.h"
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#include "dsputil.h"
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#include "mpegvideo.h"
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typedef struct CyuvDecodeContext {
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AVCodecContext *avctx;
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int width, height;
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AVFrame frame;
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} CyuvDecodeContext;
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static int cyuv_decode_init(AVCodecContext *avctx)
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{
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CyuvDecodeContext *s = avctx->priv_data;
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s->avctx = avctx;
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s->width = avctx->width;
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/* width needs to be divisible by 4 for this codec to work */
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if (s->width & 0x3)
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return -1;
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s->height = avctx->height;
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avctx->pix_fmt = PIX_FMT_YUV411P;
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avctx->has_b_frames = 0;
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return 0;
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}
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static int cyuv_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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uint8_t *buf, int buf_size)
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{
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CyuvDecodeContext *s=avctx->priv_data;
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unsigned char *y_plane;
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unsigned char *u_plane;
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unsigned char *v_plane;
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int y_ptr;
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int u_ptr;
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int v_ptr;
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/* prediction error tables (make it clear that they are signed values) */
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signed char *y_table = buf + 0;
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signed char *u_table = buf + 16;
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signed char *v_table = buf + 32;
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unsigned char y_pred, u_pred, v_pred;
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int stream_ptr;
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unsigned char cur_byte;
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int pixel_groups;
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/* sanity check the buffer size: A buffer has 3x16-bytes tables
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* followed by (height) lines each with 3 bytes to represent groups
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* of 4 pixels. Thus, the total size of the buffer ought to be:
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* (3 * 16) + height * (width * 3 / 4) */
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if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
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av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
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buf_size,
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48 + s->height * (s->width * 3 / 4));
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return -1;
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}
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/* pixel data starts 48 bytes in, after 3x16-byte tables */
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stream_ptr = 48;
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if(s->frame.data[0])
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avctx->release_buffer(avctx, &s->frame);
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s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
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s->frame.reference = 0;
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if(avctx->get_buffer(avctx, &s->frame) < 0) {
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av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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return -1;
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}
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y_plane = s->frame.data[0];
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u_plane = s->frame.data[1];
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v_plane = s->frame.data[2];
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/* iterate through each line in the height */
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for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
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y_ptr < (s->height * s->frame.linesize[0]);
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y_ptr += s->frame.linesize[0] - s->width,
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u_ptr += s->frame.linesize[1] - s->width / 4,
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v_ptr += s->frame.linesize[2] - s->width / 4) {
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/* reset predictors */
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cur_byte = buf[stream_ptr++];
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u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
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y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
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cur_byte = buf[stream_ptr++];
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v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
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y_pred += y_table[cur_byte & 0x0F];
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y_plane[y_ptr++] = y_pred;
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cur_byte = buf[stream_ptr++];
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y_pred += y_table[cur_byte & 0x0F];
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y_plane[y_ptr++] = y_pred;
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y_pred += y_table[(cur_byte & 0xF0) >> 4];
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y_plane[y_ptr++] = y_pred;
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/* iterate through the remaining pixel groups (4 pixels/group) */
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pixel_groups = s->width / 4 - 1;
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while (pixel_groups--) {
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cur_byte = buf[stream_ptr++];
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u_pred += u_table[(cur_byte & 0xF0) >> 4];
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u_plane[u_ptr++] = u_pred;
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y_pred += y_table[cur_byte & 0x0F];
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y_plane[y_ptr++] = y_pred;
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cur_byte = buf[stream_ptr++];
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v_pred += v_table[(cur_byte & 0xF0) >> 4];
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v_plane[v_ptr++] = v_pred;
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y_pred += y_table[cur_byte & 0x0F];
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y_plane[y_ptr++] = y_pred;
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cur_byte = buf[stream_ptr++];
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y_pred += y_table[cur_byte & 0x0F];
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y_plane[y_ptr++] = y_pred;
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y_pred += y_table[(cur_byte & 0xF0) >> 4];
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y_plane[y_ptr++] = y_pred;
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}
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}
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*data_size=sizeof(AVFrame);
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*(AVFrame*)data= s->frame;
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return buf_size;
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}
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static int cyuv_decode_end(AVCodecContext *avctx)
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{
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/* CyuvDecodeContext *s = avctx->priv_data;*/
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return 0;
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}
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AVCodec cyuv_decoder = {
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"cyuv",
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CODEC_TYPE_VIDEO,
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CODEC_ID_CYUV,
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sizeof(CyuvDecodeContext),
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cyuv_decode_init,
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NULL,
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cyuv_decode_end,
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cyuv_decode_frame,
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CODEC_CAP_DR1,
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NULL
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};
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