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libavcodec/cyuv.c

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00001 /*
00002  * Creative YUV (CYUV) Video Decoder
00003  *   by Mike Melanson (melanson@pcisys.net)
00004  * based on "Creative YUV (CYUV) stream format for AVI":
00005  *   http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
00006  *
00007  * Copyright (C) 2003 the ffmpeg project
00008  *
00009  * This file is part of FFmpeg.
00010  *
00011  * FFmpeg is free software; you can redistribute it and/or
00012  * modify it under the terms of the GNU Lesser General Public
00013  * License as published by the Free Software Foundation; either
00014  * version 2.1 of the License, or (at your option) any later version.
00015  *
00016  * FFmpeg is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00019  * Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License along with FFmpeg; if not, write to the Free Software
00023  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00024  */
00025 
00031 #include <stdio.h>
00032 #include <stdlib.h>
00033 #include <string.h>
00034 
00035 #include "avcodec.h"
00036 #include "dsputil.h"
00037 
00038 
00039 typedef struct CyuvDecodeContext {
00040     AVCodecContext *avctx;
00041     int width, height;
00042     AVFrame frame;
00043 } CyuvDecodeContext;
00044 
00045 static av_cold int cyuv_decode_init(AVCodecContext *avctx)
00046 {
00047     CyuvDecodeContext *s = avctx->priv_data;
00048 
00049     s->avctx = avctx;
00050     s->width = avctx->width;
00051     /* width needs to be divisible by 4 for this codec to work */
00052     if (s->width & 0x3)
00053         return -1;
00054     s->height = avctx->height;
00055     avctx->pix_fmt = PIX_FMT_YUV411P;
00056 
00057     return 0;
00058 }
00059 
00060 static int cyuv_decode_frame(AVCodecContext *avctx,
00061                              void *data, int *data_size,
00062                              AVPacket *avpkt)
00063 {
00064     const uint8_t *buf = avpkt->data;
00065     int buf_size = avpkt->size;
00066     CyuvDecodeContext *s=avctx->priv_data;
00067 
00068     unsigned char *y_plane;
00069     unsigned char *u_plane;
00070     unsigned char *v_plane;
00071     int y_ptr;
00072     int u_ptr;
00073     int v_ptr;
00074 
00075     /* prediction error tables (make it clear that they are signed values) */
00076     const signed char *y_table = (const signed char*)buf +  0;
00077     const signed char *u_table = (const signed char*)buf + 16;
00078     const signed char *v_table = (const signed char*)buf + 32;
00079 
00080     unsigned char y_pred, u_pred, v_pred;
00081     int stream_ptr;
00082     unsigned char cur_byte;
00083     int pixel_groups;
00084 
00085     if (avctx->codec_id == CODEC_ID_AURA) {
00086         y_table = u_table;
00087         u_table = v_table;
00088     }
00089     /* sanity check the buffer size: A buffer has 3x16-bytes tables
00090      * followed by (height) lines each with 3 bytes to represent groups
00091      * of 4 pixels. Thus, the total size of the buffer ought to be:
00092      *    (3 * 16) + height * (width * 3 / 4) */
00093     if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
00094         av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
00095                buf_size, 48 + s->height * (s->width * 3 / 4));
00096         return -1;
00097     }
00098 
00099     /* pixel data starts 48 bytes in, after 3x16-byte tables */
00100     stream_ptr = 48;
00101 
00102     if (s->frame.data[0])
00103         avctx->release_buffer(avctx, &s->frame);
00104 
00105     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
00106     s->frame.reference = 0;
00107     if (avctx->get_buffer(avctx, &s->frame) < 0) {
00108         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00109         return -1;
00110     }
00111 
00112     y_plane = s->frame.data[0];
00113     u_plane = s->frame.data[1];
00114     v_plane = s->frame.data[2];
00115 
00116     /* iterate through each line in the height */
00117     for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
00118          y_ptr < (s->height * s->frame.linesize[0]);
00119          y_ptr += s->frame.linesize[0] - s->width,
00120          u_ptr += s->frame.linesize[1] - s->width / 4,
00121          v_ptr += s->frame.linesize[2] - s->width / 4) {
00122 
00123         /* reset predictors */
00124         cur_byte = buf[stream_ptr++];
00125         u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
00126         y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
00127 
00128         cur_byte = buf[stream_ptr++];
00129         v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
00130         y_pred += y_table[cur_byte & 0x0F];
00131         y_plane[y_ptr++] = y_pred;
00132 
00133         cur_byte = buf[stream_ptr++];
00134         y_pred += y_table[cur_byte & 0x0F];
00135         y_plane[y_ptr++] = y_pred;
00136         y_pred += y_table[(cur_byte & 0xF0) >> 4];
00137         y_plane[y_ptr++] = y_pred;
00138 
00139         /* iterate through the remaining pixel groups (4 pixels/group) */
00140         pixel_groups = s->width / 4 - 1;
00141         while (pixel_groups--) {
00142 
00143             cur_byte = buf[stream_ptr++];
00144             u_pred += u_table[(cur_byte & 0xF0) >> 4];
00145             u_plane[u_ptr++] = u_pred;
00146             y_pred += y_table[cur_byte & 0x0F];
00147             y_plane[y_ptr++] = y_pred;
00148 
00149             cur_byte = buf[stream_ptr++];
00150             v_pred += v_table[(cur_byte & 0xF0) >> 4];
00151             v_plane[v_ptr++] = v_pred;
00152             y_pred += y_table[cur_byte & 0x0F];
00153             y_plane[y_ptr++] = y_pred;
00154 
00155             cur_byte = buf[stream_ptr++];
00156             y_pred += y_table[cur_byte & 0x0F];
00157             y_plane[y_ptr++] = y_pred;
00158             y_pred += y_table[(cur_byte & 0xF0) >> 4];
00159             y_plane[y_ptr++] = y_pred;
00160 
00161         }
00162     }
00163 
00164     *data_size=sizeof(AVFrame);
00165     *(AVFrame*)data= s->frame;
00166 
00167     return buf_size;
00168 }
00169 
00170 static av_cold int cyuv_decode_end(AVCodecContext *avctx)
00171 {
00172     CyuvDecodeContext *s = avctx->priv_data;
00173 
00174     if (s->frame.data[0])
00175         avctx->release_buffer(avctx, &s->frame);
00176 
00177     return 0;
00178 }
00179 
00180 #if CONFIG_AURA_DECODER
00181 AVCodec aura_decoder = {
00182     "aura",
00183     AVMEDIA_TYPE_VIDEO,
00184     CODEC_ID_AURA,
00185     sizeof(CyuvDecodeContext),
00186     cyuv_decode_init,
00187     NULL,
00188     cyuv_decode_end,
00189     cyuv_decode_frame,
00190     CODEC_CAP_DR1,
00191     NULL,
00192     .long_name = NULL_IF_CONFIG_SMALL("Auravision AURA"),
00193 };
00194 #endif
00195 
00196 #if CONFIG_CYUV_DECODER
00197 AVCodec cyuv_decoder = {
00198     "cyuv",
00199     AVMEDIA_TYPE_VIDEO,
00200     CODEC_ID_CYUV,
00201     sizeof(CyuvDecodeContext),
00202     cyuv_decode_init,
00203     NULL,
00204     cyuv_decode_end,
00205     cyuv_decode_frame,
00206     CODEC_CAP_DR1,
00207     NULL,
00208     .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
00209 };
00210 #endif

Generated on Fri Sep 16 2011 17:17:35 for FFmpeg by  doxygen 1.7.1