099bc252c6
Here it even leads to the complete removal of the context. Reviewed-by: Paul B Mahol <onemda@gmail.com> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
140 lines
4.1 KiB
C
140 lines
4.1 KiB
C
/*
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* Winnov WNV1 codec
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* Copyright (c) 2005 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
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* Winnov WNV1 codec.
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*/
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#define BITSTREAM_READER_LE
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#include "avcodec.h"
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#include "get_bits.h"
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#include "internal.h"
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static const uint16_t code_tab[16][2] = {
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{ 0x17F, 9 }, { 0xBF, 8 }, { 0x5F, 7 }, { 0x2F, 6 }, { 0x17, 5 }, { 0x0B, 4 }, { 0x005, 3 },
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{ 0x000, 1 },
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{ 0x01, 3 }, { 0x03, 4 }, { 0x07, 5 }, { 0x0F, 6 }, { 0x1F, 7 }, { 0x3F, 8 }, { 0x07F, 9 }, { 0xFF, 8 }
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};
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#define CODE_VLC_BITS 9
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static VLC code_vlc;
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/* returns modified base_value */
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static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
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{
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int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1);
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if (v == 15)
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return get_bits(gb, 8 - shift) << shift;
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else
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return base_value + ((v - 7U) << shift);
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}
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static int decode_frame(AVCodecContext *avctx,
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void *data, int *got_frame,
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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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AVFrame * const p = data;
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GetBitContext gb;
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unsigned char *Y,*U,*V;
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int i, j, ret, shift;
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int prev_y = 0, prev_u = 0, prev_v = 0;
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if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
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av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
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return AVERROR_INVALIDDATA;
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}
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if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
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return ret;
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p->key_frame = 1;
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if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)
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return ret;
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if (buf[2] >> 4 == 6)
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shift = 2;
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else {
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shift = 8 - (buf[2] >> 4);
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if (shift > 4) {
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avpriv_request_sample(avctx,
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"Unknown WNV1 frame header value %i",
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buf[2] >> 4);
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shift = 4;
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}
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if (shift < 1) {
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avpriv_request_sample(avctx,
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"Unknown WNV1 frame header value %i",
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buf[2] >> 4);
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shift = 1;
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}
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}
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Y = p->data[0];
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U = p->data[1];
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V = p->data[2];
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for (j = 0; j < avctx->height; j++) {
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for (i = 0; i < avctx->width / 2; i++) {
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Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);
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prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);
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prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);
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prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);
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}
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Y += p->linesize[0];
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U += p->linesize[1];
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V += p->linesize[2];
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}
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*got_frame = 1;
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return buf_size;
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}
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static av_cold int decode_init(AVCodecContext *avctx)
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{
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static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
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avctx->pix_fmt = AV_PIX_FMT_YUV422P;
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code_vlc.table = code_table;
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code_vlc.table_allocated = 1 << CODE_VLC_BITS;
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init_vlc(&code_vlc, CODE_VLC_BITS, 16,
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&code_tab[0][1], 4, 2,
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&code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | INIT_VLC_LE);
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return 0;
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}
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AVCodec ff_wnv1_decoder = {
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.name = "wnv1",
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.long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_WNV1,
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.init = decode_init,
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.decode = decode_frame,
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.capabilities = AV_CODEC_CAP_DR1,
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};
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