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ffmpeg / libavcodec / cyuv.c @ e20c4069

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/*
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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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#include "bswap.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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    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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    *data_size = 0;
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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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      printf ("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.reference = 0;
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    if(avctx->get_buffer(avctx, &s->frame) < 0) {
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        fprintf(stderr, "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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    0,
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    NULL
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};
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