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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 4:
00059     case 8:
00060         avctx->pix_fmt = PIX_FMT_PAL8;
00061         break;
00062     case 24:
00063         avctx->pix_fmt = PIX_FMT_BGR24;
00064         break;
00065     default:
00066         av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
00067         return -1;
00068     }
00069 
00070     s->frame.data[0] = NULL;
00071 
00072     return 0;
00073 }
00074 
00075 static int msrle_decode_frame(AVCodecContext *avctx,
00076                               void *data, int *data_size,
00077                               AVPacket *avpkt)
00078 {
00079     const uint8_t *buf = avpkt->data;
00080     int buf_size = avpkt->size;
00081     MsrleContext *s = avctx->priv_data;
00082     int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
00083 
00084     s->buf = buf;
00085     s->size = buf_size;
00086 
00087     s->frame.reference = 1;
00088     s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
00089     if (avctx->reget_buffer(avctx, &s->frame)) {
00090         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
00091         return -1;
00092     }
00093 
00094     if (s->avctx->palctrl) {
00095         /* make the palette available */
00096         memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
00097         if (s->avctx->palctrl->palette_changed) {
00098             s->frame.palette_has_changed = 1;
00099             s->avctx->palctrl->palette_changed = 0;
00100         }
00101     }
00102 
00103     /* FIXME how to correctly detect RLE ??? */
00104     if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
00105         int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
00106         uint8_t *ptr = s->frame.data[0];
00107         uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
00108         int i, j;
00109 
00110         for (i = 0; i < avctx->height; i++) {
00111             if (avctx->bits_per_coded_sample == 4) {
00112                 for (j = 0; j < avctx->width - 1; j += 2) {
00113                     ptr[j+0] = buf[j>>1] >> 4;
00114                     ptr[j+1] = buf[j>>1] & 0xF;
00115                 }
00116                 if (avctx->width & 1)
00117                     ptr[j+0] = buf[j>>1] >> 4;
00118             } else {
00119                 memcpy(ptr, buf, linesize);
00120             }
00121             buf -= istride;
00122             ptr += s->frame.linesize[0];
00123         }
00124     } else {
00125         ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, buf, buf_size);
00126     }
00127 
00128     *data_size = sizeof(AVFrame);
00129     *(AVFrame*)data = s->frame;
00130 
00131     /* report that the buffer was completely consumed */
00132     return buf_size;
00133 }
00134 
00135 static av_cold int msrle_decode_end(AVCodecContext *avctx)
00136 {
00137     MsrleContext *s = avctx->priv_data;
00138 
00139     /* release the last frame */
00140     if (s->frame.data[0])
00141         avctx->release_buffer(avctx, &s->frame);
00142 
00143     return 0;
00144 }
00145 
00146 AVCodec msrle_decoder = {
00147     "msrle",
00148     AVMEDIA_TYPE_VIDEO,
00149     CODEC_ID_MSRLE,
00150     sizeof(MsrleContext),
00151     msrle_decode_init,
00152     NULL,
00153     msrle_decode_end,
00154     msrle_decode_frame,
00155     CODEC_CAP_DR1,
00156     .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
00157 };

Generated on Fri Sep 16 2011 17:17:41 for FFmpeg by  doxygen 1.7.1