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319 lines
9.9 KiB
319 lines
9.9 KiB
/* |
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* Escape 130 Video Decoder |
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* Copyright (C) 2008 Eli Friedman (eli.friedman <at> gmail.com) |
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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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#include "avcodec.h" |
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#define BITSTREAM_READER_LE |
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#include "get_bits.h" |
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typedef struct Escape130Context { |
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AVFrame frame; |
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uint8_t *bases; |
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} Escape130Context; |
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/** |
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* Initialize the decoder |
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* @param avctx decoder context |
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* @return 0 success, negative on error |
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*/ |
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static av_cold int escape130_decode_init(AVCodecContext *avctx) |
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{ |
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Escape130Context *s = avctx->priv_data; |
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avctx->pix_fmt = PIX_FMT_YUV420P; |
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if((avctx->width&1) || (avctx->height&1)){ |
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av_log(avctx, AV_LOG_ERROR, "Dimensions are not a multiple of the block size\n"); |
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return AVERROR(EINVAL); |
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} |
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s->bases= av_malloc(avctx->width * avctx->height /4); |
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return 0; |
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} |
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static av_cold int escape130_decode_close(AVCodecContext *avctx) |
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{ |
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Escape130Context *s = avctx->priv_data; |
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if (s->frame.data[0]) |
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avctx->release_buffer(avctx, &s->frame); |
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av_freep(&s->bases); |
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return 0; |
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} |
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static unsigned decode_skip_count(GetBitContext* gb) { |
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unsigned value; |
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// This function reads a maximum of 27 bits, |
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// which is within the padding space |
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if (get_bits_left(gb) < 1+3) |
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return -1; |
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value = get_bits1(gb); |
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if (value) |
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return 0; |
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value = get_bits(gb, 3); |
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if (value) |
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return value; |
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value = get_bits(gb, 8); |
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if (value) |
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return value + 7; |
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value = get_bits(gb, 15); |
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if (value) |
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return value + 262; |
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return -1; |
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} |
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/** |
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* Decode a single frame |
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* @param avctx decoder context |
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* @param data decoded frame |
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* @param data_size size of the decoded frame |
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* @param buf input buffer |
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* @param buf_size input buffer size |
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* @return 0 success, -1 on error |
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*/ |
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static int escape130_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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Escape130Context *s = avctx->priv_data; |
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GetBitContext gb; |
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unsigned i; |
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uint8_t *old_y, *old_cb, *old_cr, |
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*new_y, *new_cb, *new_cr; |
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unsigned old_y_stride, old_cb_stride, old_cr_stride, |
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new_y_stride, new_cb_stride, new_cr_stride; |
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unsigned total_blocks = avctx->width * avctx->height / 4, |
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block_index, row_index = 0; |
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unsigned y[4] = {0}, cb = 16, cr = 16; |
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unsigned skip = -1; |
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unsigned y_base = 0; |
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uint8_t *yb= s->bases; |
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AVFrame new_frame = { { 0 } }; |
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init_get_bits(&gb, buf, buf_size * 8); |
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if (get_bits_left(&gb) < 128) |
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return -1; |
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// Header; no useful information in here |
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skip_bits_long(&gb, 128); |
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new_frame.reference = 3; |
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if (avctx->get_buffer(avctx, &new_frame)) { |
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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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new_y = new_frame.data[0]; |
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new_cb = new_frame.data[1]; |
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new_cr = new_frame.data[2]; |
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new_y_stride = new_frame.linesize[0]; |
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new_cb_stride = new_frame.linesize[1]; |
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new_cr_stride = new_frame.linesize[2]; |
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old_y = s->frame.data[0]; |
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old_cb = s->frame.data[1]; |
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old_cr = s->frame.data[2]; |
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old_y_stride = s->frame.linesize[0]; |
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old_cb_stride = s->frame.linesize[1]; |
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old_cr_stride = s->frame.linesize[2]; |
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av_log(avctx, AV_LOG_DEBUG, |
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"Strides: %i, %i\n", |
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new_y_stride, new_cb_stride); |
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for (block_index = 0; block_index < total_blocks; block_index++) { |
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// Note that this call will make us skip the rest of the blocks |
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// if the frame prematurely ends |
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if (skip == -1) |
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skip = decode_skip_count(&gb); |
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if (skip) { |
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if (old_y) { |
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y[0] = old_y[0] / 4; |
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y[1] = old_y[1] / 4; |
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y[2] = old_y[old_y_stride] / 4; |
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y[3] = old_y[old_y_stride+1] / 4; |
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y_base= yb[0]; |
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cb = old_cb[0] / 8; |
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cr = old_cr[0] / 8; |
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} else { |
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y_base=y[0] = y[1] = y[2] = y[3] = 0; |
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cb = cr = 16; |
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} |
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} else { |
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if (get_bits1(&gb)) { |
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static const uint8_t offset_table[] = {2, 4, 10, 20}; |
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static const int8_t sign_table[64][4] = |
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{ {0, 0, 0, 0}, |
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{-1, 1, 0, 0}, |
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{1, -1, 0, 0}, |
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{-1, 0, 1, 0}, |
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{-1, 1, 1, 0}, |
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{0, -1, 1, 0}, |
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{1, -1, 1, 0}, |
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{-1, -1, 1, 0}, |
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{1, 0, -1, 0}, |
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{0, 1, -1, 0}, |
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{1, 1, -1, 0}, |
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{-1, 1, -1, 0}, |
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{1, -1, -1, 0}, |
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{-1, 0, 0, 1}, |
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{-1, 1, 0, 1}, |
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{0, -1, 0, 1}, |
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{0, 0, 0, 0}, |
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{1, -1, 0, 1}, |
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{-1, -1, 0, 1}, |
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{-1, 0, 1, 1}, |
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{-1, 1, 1, 1}, |
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{0, -1, 1, 1}, |
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{1, -1, 1, 1}, |
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{-1, -1, 1, 1}, |
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{0, 0, -1, 1}, |
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{1, 0, -1, 1}, |
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{-1, 0, -1, 1}, |
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{0, 1, -1, 1}, |
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{1, 1, -1, 1}, |
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{-1, 1, -1, 1}, |
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{0, -1, -1, 1}, |
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{1, -1, -1, 1}, |
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{0, 0, 0, 0}, |
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{-1, -1, -1, 1}, |
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{1, 0, 0, -1}, |
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{0, 1, 0, -1}, |
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{1, 1, 0, -1}, |
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{-1, 1, 0, -1}, |
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{1, -1, 0, -1}, |
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{0, 0, 1, -1}, |
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{1, 0, 1, -1}, |
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{-1, 0, 1, -1}, |
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{0, 1, 1, -1}, |
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{1, 1, 1, -1}, |
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{-1, 1, 1, -1}, |
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{0, -1, 1, -1}, |
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{1, -1, 1, -1}, |
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{-1, -1, 1, -1}, |
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{0, 0, 0, 0}, |
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{1, 0, -1, -1}, |
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{0, 1, -1, -1}, |
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{1, 1, -1, -1}, |
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{-1, 1, -1, -1}, |
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{1, -1, -1, -1} }; |
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unsigned sign_selector = get_bits(&gb, 6); |
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unsigned difference_selector = get_bits(&gb, 2); |
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y_base = 2 * get_bits(&gb, 5); |
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for (i = 0; i < 4; i++) { |
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y[i] = av_clip((int)y_base + offset_table[difference_selector] * |
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sign_table[sign_selector][i], 0, 63); |
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} |
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} else if (get_bits1(&gb)) { |
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if (get_bits1(&gb)) { |
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y_base = get_bits(&gb, 6); |
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} else { |
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unsigned adjust_index = get_bits(&gb, 3); |
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static const int8_t adjust[] = {-4, -3, -2, -1, 1, 2, 3, 4}; |
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y_base = (y_base + adjust[adjust_index]) & 63; |
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} |
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for (i = 0; i < 4; i++) |
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y[i] = y_base; |
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} |
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if (get_bits1(&gb)) { |
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if (get_bits1(&gb)) { |
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cb = get_bits(&gb, 5); |
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cr = get_bits(&gb, 5); |
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} else { |
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unsigned adjust_index = get_bits(&gb, 3); |
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static const int8_t adjust[2][8] = |
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{ { 1, 1, 0, -1, -1, -1, 0, 1 }, |
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{ 0, 1, 1, 1, 0, -1, -1, -1 } }; |
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cb = (cb + adjust[0][adjust_index]) & 31; |
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cr = (cr + adjust[1][adjust_index]) & 31; |
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} |
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} |
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} |
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*yb++= y_base; |
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new_y[0] = y[0] * 4; |
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new_y[1] = y[1] * 4; |
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new_y[new_y_stride] = y[2] * 4; |
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new_y[new_y_stride + 1] = y[3] * 4; |
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*new_cb = cb * 8; |
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*new_cr = cr * 8; |
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if (old_y) |
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old_y += 2, old_cb++, old_cr++; |
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new_y += 2, new_cb++, new_cr++; |
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row_index++; |
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if (avctx->width / 2 == row_index) { |
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row_index = 0; |
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if (old_y) { |
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old_y += old_y_stride * 2 - avctx->width; |
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old_cb += old_cb_stride - avctx->width / 2; |
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old_cr += old_cr_stride - avctx->width / 2; |
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} |
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new_y += new_y_stride * 2 - avctx->width; |
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new_cb += new_cb_stride - avctx->width / 2; |
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new_cr += new_cr_stride - avctx->width / 2; |
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} |
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skip--; |
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} |
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av_log(avctx, AV_LOG_DEBUG, |
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"Escape sizes: %i, %i\n", |
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buf_size, get_bits_count(&gb) / 8); |
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if (s->frame.data[0]) |
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avctx->release_buffer(avctx, &s->frame); |
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*(AVFrame*)data = s->frame = new_frame; |
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*data_size = sizeof(AVFrame); |
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return buf_size; |
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} |
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AVCodec ff_escape130_decoder = { |
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.name = "escape130", |
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.type = AVMEDIA_TYPE_VIDEO, |
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.id = AV_CODEC_ID_ESCAPE130, |
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.priv_data_size = sizeof(Escape130Context), |
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.init = escape130_decode_init, |
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.close = escape130_decode_close, |
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.decode = escape130_decode_frame, |
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.capabilities = CODEC_CAP_DR1, |
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.long_name = NULL_IF_CONFIG_SMALL("Escape 130"), |
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};
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