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* TechSmith Camtasia decoder
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* Copyright (c) 2004 Konstantin Shishkov
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* This library 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 of the License, or (at your option) any later version.
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* This library 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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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* TechSmith Camtasia decoder
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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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* Supports: BGR8,BGR555,BGR24 - only BGR8 and BGR555 tested
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typedef struct TsccContext {
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AVCodecContext *avctx;
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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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* Decode RLE - almost identical to Windows BMP RLE8
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* and enhanced to bigger color depths
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static int decode_rle(CamtasiaContext *c, unsigned int srcsize)
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unsigned char *src = c->decomp_buf;
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unsigned char *output, *output_end;
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int p1, p2, line=c->height, pos=0, i;
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output = c->pic.data[0] + (c->height - 1) * c->pic.linesize[0];
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output_end = c->pic.data[0] + (c->height) * c->pic.linesize[0];
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while(src < c->decomp_buf + srcsize) {
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if(p1 == 0) { //Escape code
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if(p2 == 0) { //End-of-line
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output = c->pic.data[0] + (--line) * c->pic.linesize[0];
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} else if(p2 == 1) { //End-of-picture
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} else if(p2 == 2) { //Skip
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output = c->pic.data[0] + line * c->pic.linesize[0] + pos * (c->bpp / 8);
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if (output + p2 * (c->bpp / 8) > output_end) {
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src += p2 * (c->bpp / 8);
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for(i = 0; i < p2 * (c->bpp / 8); i++) {
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// RLE8 copy is actually padded - and runs are not!
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if(c->bpp == 8 && (p2 & 1)) {
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} else { //Run of pixels
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int pix[4]; //original pixel
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case 8: pix[0] = *src++;
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case 16: pix[0] = *src++;
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case 24: pix[0] = *src++;
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case 32: pix[0] = *src++;
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if (output + p1 * (c->bpp / 8) > output_end)
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for(i = 0; i < p1; i++) {
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case 8: *output++ = pix[0];
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case 16: *output++ = pix[0];
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case 24: *output++ = pix[0];
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case 32: *output++ = pix[0];
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av_log(c->avctx, AV_LOG_ERROR, "Camtasia warning: no End-of-picture code\n");
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static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
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CamtasiaContext * const c = (CamtasiaContext *)avctx->priv_data;
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unsigned char *encoded = (unsigned char *)buf;
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unsigned char *outptr;
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int zret; // Zlib return code
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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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outptr = c->pic.data[0]; // Output image pointer
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zret = inflateReset(&(c->zstream));
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av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
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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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if(zret != Z_DATA_ERROR)
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decode_rle(c, 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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av_log(avctx, AV_LOG_ERROR, "BUG! Zlib support not compiled in frame decoder.\n");
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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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static int decode_init(AVCodecContext *avctx)
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CamtasiaContext * const c = (CamtasiaContext *)avctx->priv_data;
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int zret; // Zlib return code
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avctx->has_b_frames = 0;
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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->height, avctx->width) < 0) {
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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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av_log(avctx, AV_LOG_ERROR, "Zlib support not compiled.\n");
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switch(avctx->bits_per_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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avctx->pix_fmt = PIX_FMT_BGR24;
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case 32: avctx->pix_fmt = PIX_FMT_RGBA32; break;
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default: av_log(avctx, AV_LOG_ERROR, "Camtasia error: unknown depth %i bpp\n", avctx->bits_per_sample);
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c->bpp = avctx->bits_per_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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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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av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
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* Uninit tscc decoder
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static int decode_end(AVCodecContext *avctx)
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CamtasiaContext * const c = (CamtasiaContext *)avctx->priv_data;
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av_freep(&c->decomp_buf);
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avctx->release_buffer(avctx, &c->pic);
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inflateEnd(&(c->zstream));
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AVCodec tscc_decoder = {
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sizeof(CamtasiaContext),