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ffmpeg / libavcodec / tscc.c @ 5d44b2a1

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/*
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 * TechSmith Camtasia decoder
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 * Copyright (c) 2004 Konstantin Shishkov
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg 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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 * FFmpeg 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 FFmpeg; 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 libavcodec/tscc.c
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 * TechSmith Camtasia decoder
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 *
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 * Fourcc: TSCC
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 *
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 * Codec is very simple:
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 *  it codes picture (picture difference, really)
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 *  with algorithm almost identical to Windows RLE8,
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 *  only without padding and with greater pixel sizes,
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 *  then this coded picture is packed with ZLib
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 *
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 * Supports: BGR8,BGR555,BGR24 - only BGR8 and BGR555 tested
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 *
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include "avcodec.h"
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#include "msrledec.h"
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#include <zlib.h>
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/*
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 * Decoder context
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 */
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typedef struct TsccContext {
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    AVCodecContext *avctx;
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    AVFrame pic;
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    // Bits per pixel
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    int bpp;
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    // Decompressed data size
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    unsigned int decomp_size;
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    // Decompression buffer
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    unsigned char* decomp_buf;
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    int height;
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    z_stream zstream;
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} CamtasiaContext;
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/*
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 *
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 * Decode a frame
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 *
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 */
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static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
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{
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    CamtasiaContext * const c = avctx->priv_data;
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    const unsigned char *encoded = buf;
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    unsigned char *outptr;
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    int zret; // Zlib return code
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    int len = buf_size;
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    if(c->pic.data[0])
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            avctx->release_buffer(avctx, &c->pic);
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    c->pic.reference = 1;
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    c->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
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    if(avctx->get_buffer(avctx, &c->pic) < 0){
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        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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        return -1;
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    }
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    outptr = c->pic.data[0]; // Output image pointer
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    zret = inflateReset(&(c->zstream));
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    if (zret != Z_OK) {
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        av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
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        return -1;
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    }
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    c->zstream.next_in = encoded;
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    c->zstream.avail_in = len;
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    c->zstream.next_out = c->decomp_buf;
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    c->zstream.avail_out = c->decomp_size;
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    zret = inflate(&(c->zstream), Z_FINISH);
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    // Z_DATA_ERROR means empty picture
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    if ((zret != Z_OK) && (zret != Z_STREAM_END) && (zret != Z_DATA_ERROR)) {
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        av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", zret);
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        return -1;
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    }
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    if(zret != Z_DATA_ERROR)
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        ff_msrle_decode(avctx, (AVPicture*)&c->pic, c->bpp, c->decomp_buf, c->zstream.avail_out);
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    /* make the palette available on the way out */
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    if (c->avctx->pix_fmt == PIX_FMT_PAL8) {
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        memcpy(c->pic.data[1], c->avctx->palctrl->palette, AVPALETTE_SIZE);
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        if (c->avctx->palctrl->palette_changed) {
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            c->pic.palette_has_changed = 1;
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            c->avctx->palctrl->palette_changed = 0;
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        }
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = c->pic;
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    /* always report that the buffer was completely consumed */
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    return buf_size;
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}
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/*
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 *
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 * Init tscc decoder
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 *
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 */
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static av_cold int decode_init(AVCodecContext *avctx)
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{
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    CamtasiaContext * const c = avctx->priv_data;
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    int zret; // Zlib return code
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    c->avctx = avctx;
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    c->pic.data[0] = NULL;
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    c->height = avctx->height;
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    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
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        return 1;
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    }
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    // Needed if zlib unused or init aborted before inflateInit
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    memset(&(c->zstream), 0, sizeof(z_stream));
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    switch(avctx->bits_per_coded_sample){
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    case  8: avctx->pix_fmt = PIX_FMT_PAL8; break;
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    case 16: avctx->pix_fmt = PIX_FMT_RGB555; 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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    case 32: avctx->pix_fmt = PIX_FMT_RGB32; break;
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    default: av_log(avctx, AV_LOG_ERROR, "Camtasia error: unknown depth %i bpp\n", avctx->bits_per_coded_sample);
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             return -1;
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    }
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    c->bpp = avctx->bits_per_coded_sample;
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    c->decomp_size = (avctx->width * c->bpp + (avctx->width + 254) / 255 + 2) * avctx->height + 2;//RLE in the 'best' case
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    /* Allocate decompression buffer */
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    if (c->decomp_size) {
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        if ((c->decomp_buf = av_malloc(c->decomp_size)) == NULL) {
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            av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
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            return 1;
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        }
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    }
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    c->zstream.zalloc = Z_NULL;
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    c->zstream.zfree = Z_NULL;
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    c->zstream.opaque = Z_NULL;
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    zret = inflateInit(&(c->zstream));
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    if (zret != Z_OK) {
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        av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
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        return 1;
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    }
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    return 0;
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}
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/*
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 *
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 * Uninit tscc decoder
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 *
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 */
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static av_cold int decode_end(AVCodecContext *avctx)
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{
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    CamtasiaContext * const c = avctx->priv_data;
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    av_freep(&c->decomp_buf);
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    if (c->pic.data[0])
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        avctx->release_buffer(avctx, &c->pic);
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    inflateEnd(&(c->zstream));
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    return 0;
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}
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AVCodec tscc_decoder = {
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        "camtasia",
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        CODEC_TYPE_VIDEO,
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        CODEC_ID_TSCC,
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        sizeof(CamtasiaContext),
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        decode_init,
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        NULL,
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        decode_end,
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        decode_frame,
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        CODEC_CAP_DR1,
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        .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Capture Codec"),
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};
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