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ffmpeg / libavcodec / msrle.c @ 2912e87a

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/*
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 * Micrsoft RLE Video Decoder
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 * Copyright (C) 2003 the ffmpeg project
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav 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 Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net)
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 * For more information about the MS RLE format, visit:
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 *   http://www.pcisys.net/~melanson/codecs/
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 *
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 * The MS RLE decoder outputs PAL8 colorspace data.
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 *
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 * Note that this decoder expects the palette colors from the end of the
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 * BITMAPINFO header passed through palctrl.
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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 "avcodec.h"
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#include "dsputil.h"
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#include "msrledec.h"
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typedef struct MsrleContext {
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    AVCodecContext *avctx;
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    AVFrame frame;
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    const unsigned char *buf;
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    int size;
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} MsrleContext;
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static av_cold int msrle_decode_init(AVCodecContext *avctx)
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{
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    MsrleContext *s = avctx->priv_data;
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    s->avctx = avctx;
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    switch (avctx->bits_per_coded_sample) {
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    case 4:
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    case 8:
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        avctx->pix_fmt = PIX_FMT_PAL8;
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        break;
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    case 24:
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        avctx->pix_fmt = PIX_FMT_BGR24;
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        break;
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    default:
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        av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
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        return -1;
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    }
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    s->frame.data[0] = NULL;
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    return 0;
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}
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static int msrle_decode_frame(AVCodecContext *avctx,
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                              void *data, int *data_size,
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                              AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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    int buf_size = avpkt->size;
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    MsrleContext *s = avctx->priv_data;
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    int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
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    s->buf = buf;
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    s->size = buf_size;
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    s->frame.reference = 1;
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    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
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    if (avctx->reget_buffer(avctx, &s->frame)) {
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        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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        return -1;
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    }
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    if (s->avctx->palctrl) {
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        /* make the palette available */
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        memcpy(s->frame.data[1], s->avctx->palctrl->palette, AVPALETTE_SIZE);
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        if (s->avctx->palctrl->palette_changed) {
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            s->frame.palette_has_changed = 1;
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            s->avctx->palctrl->palette_changed = 0;
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        }
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    }
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    /* FIXME how to correctly detect RLE ??? */
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    if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
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        int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
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        uint8_t *ptr = s->frame.data[0];
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        uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
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        int i, j;
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        for (i = 0; i < avctx->height; i++) {
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            if (avctx->bits_per_coded_sample == 4) {
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                for (j = 0; j < avctx->width - 1; j += 2) {
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                    ptr[j+0] = buf[j>>1] >> 4;
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                    ptr[j+1] = buf[j>>1] & 0xF;
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                }
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                if (avctx->width & 1)
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                    ptr[j+0] = buf[j>>1] >> 4;
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            } else {
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                memcpy(ptr, buf, linesize);
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            }
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            buf -= istride;
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            ptr += s->frame.linesize[0];
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        }
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    } else {
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        ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, buf, buf_size);
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = s->frame;
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    /* report that the buffer was completely consumed */
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    return buf_size;
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}
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static av_cold int msrle_decode_end(AVCodecContext *avctx)
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{
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    MsrleContext *s = avctx->priv_data;
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    /* release the last frame */
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    if (s->frame.data[0])
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        avctx->release_buffer(avctx, &s->frame);
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    return 0;
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}
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AVCodec ff_msrle_decoder = {
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    "msrle",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_MSRLE,
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    sizeof(MsrleContext),
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    msrle_decode_init,
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    NULL,
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    msrle_decode_end,
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    msrle_decode_frame,
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    CODEC_CAP_DR1,
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    .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
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};