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libavcodec/msrle.c

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00001 /*
00002  * Micrsoft RLE Video Decoder
00003  * Copyright (C) 2003 the ffmpeg project
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00034 #include <stdio.h>
00035 #include <stdlib.h>
00036 #include <string.h>
00037 
00038 #include "avcodec.h"
00039 #include "dsputil.h"
00040 #include "msrledec.h"
00041 
00042 typedef struct MsrleContext {
00043     AVCodecContext *avctx;
00044     AVFrame frame;
00045 
00046     const unsigned char *buf;
00047     int size;
00048 
00049 } MsrleContext;
00050 
00051 static av_cold int msrle_decode_init(AVCodecContext *avctx)
00052 {
00053     MsrleContext *s = avctx->priv_data;
00054 
00055     s->avctx = avctx;
00056 
00057     switch (avctx->bits_per_coded_sample) {
00058     case 1:
00059         avctx->pix_fmt = PIX_FMT_MONOWHITE;
00060         break;
00061     case 4:
00062     case 8:
00063         avctx->pix_fmt = PIX_FMT_PAL8;
00064         break;
00065     case 24:
00066         avctx->pix_fmt = PIX_FMT_BGR24;
00067         break;
00068     default:
00069         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
00070         return -1;
00071     }
00072 
00073     avcodec_get_frame_defaults(&s->frame);
00074     s->frame.data[0] = NULL;
00075 
00076     return 0;
00077 }
00078 
00079 static int msrle_decode_frame(AVCodecContext *avctx,
00080                               void *data, int *data_size,
00081                               AVPacket *avpkt)
00082 {
00083     const uint8_t *buf = avpkt->data;
00084     int buf_size = avpkt->size;
00085     MsrleContext *s = avctx->priv_data;
00086     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
00087 
00088     s->buf = buf;
00089     s->size = buf_size;
00090 
00091     s->frame.reference = 1;
00092     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
00093     if (avctx->reget_buffer(avctx, &s->frame)) {
00094         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
00095         return -1;
00096     }
00097 
00098     if (s->avctx->palctrl) {
00099         /* make the palette available */
00100         memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
00101         if (s->avctx->palctrl->palette_changed) {
00102             s->frame.palette_has_changed = 1;
00103             s->avctx->palctrl->palette_changed = 0;
00104         }
00105     }
00106 
00107     /* FIXME how to correctly detect RLE ??? */
00108     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
00109         int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
00110         uint8_t *ptr = s->frame.data[0];
00111         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
00112         int i, j;
00113 
00114         for (i = 0; i < avctx->height; i++) {
00115             if (avctx->bits_per_coded_sample == 4) {
00116                 for (j = 0; j < avctx->width - 1; j += 2) {
00117                     ptr[j+0] = buf[j>>1] >> 4;
00118                     ptr[j+1] = buf[j>>1] & 0xF;
00119                 }
00120                 if (avctx->width & 1)
00121                     ptr[j+0] = buf[j>>1] >> 4;
00122             } else {
00123                 memcpy(ptr, buf, linesize);
00124             }
00125             buf -= istride;
00126             ptr += s->frame.linesize[0];
00127         }
00128     } else {
00129         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, buf, buf_size);
00130     }
00131 
00132     *data_size = sizeof(AVFrame);
00133     *(AVFrame*)data = s->frame;
00134 
00135     /* report that the buffer was completely consumed */
00136     return buf_size;
00137 }
00138 
00139 static av_cold int msrle_decode_end(AVCodecContext *avctx)
00140 {
00141     MsrleContext *s = avctx->priv_data;
00142 
00143     /* release the last frame */
00144     if (s->frame.data[0])
00145         avctx->release_buffer(avctx, &s->frame);
00146 
00147     return 0;
00148 }
00149 
00150 AVCodec ff_msrle_decoder = {
00151     "msrle",
00152     AVMEDIA_TYPE_VIDEO,
00153     CODEC_ID_MSRLE,
00154     sizeof(MsrleContext),
00155     msrle_decode_init,
00156     NULL,
00157     msrle_decode_end,
00158     msrle_decode_frame,
00159     CODEC_CAP_DR1,
00160     .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
00161 };

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