mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 4083 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
Mike Melanson
20 years ago
parent
cec1f05fd7
commit
a8a15e9db2
7 changed files with 177 additions and 2 deletions
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/*
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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 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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* |
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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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* |
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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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* |
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*/ |
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/**
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* @file wnv1.c |
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* Winnov WNV1 codec. |
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*/ |
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#include "avcodec.h" |
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#include "common.h" |
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typedef struct WNV1Context{ |
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AVCodecContext *avctx; |
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AVFrame pic; |
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int shift; |
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/* bit buffer */ |
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unsigned long bitbuf; |
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int bits; |
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uint8_t *buf; |
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} WNV1Context; |
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/* returns modified base_value */ |
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static inline int wnv1_get_code(WNV1Context *w, int base_value) |
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{ |
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int v = 0; |
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if (w->bits < 16) { /* need to fill bit buffer */ |
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w->bitbuf |= LE_16(w->buf) << w->bits; |
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w->buf += 2; |
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w->bits += 16; |
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} |
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/* escape code */ |
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if ((w->bitbuf & 0xFF) == 0xFF) { |
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w->bitbuf >>= 8; |
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w->bits -= 8; |
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if (w->bits < 16) { /* need to fill bit buffer */ |
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w->bitbuf |= LE_16(w->buf) << w->bits; |
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w->buf += 2; |
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w->bits += 16; |
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} |
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v = w->bitbuf & (0xFF >> w->shift); |
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w->bitbuf >>= 8 - w->shift; |
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w->bits -= 8 - w->shift; |
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return v << w->shift; |
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} |
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/* zero code */ |
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if (!(w->bitbuf & 1)) { |
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w->bitbuf >>= 1; |
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w->bits--; |
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return base_value; |
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} |
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/* reversed unary code and sign */ |
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while (w->bits && w->bitbuf & 1) { |
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w->bitbuf >>= 1; |
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w->bits--; |
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v++; |
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} |
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w->bitbuf >>= 1; |
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w->bits--; |
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if(w->bitbuf & 1) |
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v = -v; |
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w->bitbuf >>= 1; |
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w->bits--; |
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v <<= w->shift; |
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return base_value + v; |
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} |
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static int decode_frame(AVCodecContext *avctx,
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void *data, int *data_size, |
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uint8_t *buf, int buf_size) |
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{ |
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WNV1Context * const l = avctx->priv_data; |
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AVFrame * const p= (AVFrame*)&l->pic; |
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unsigned char *Y,*U,*V; |
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int i, j; |
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int prev_y = 0, prev_u = 0, prev_v = 0; |
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if(p->data[0]) |
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avctx->release_buffer(avctx, p); |
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p->reference = 0; |
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if(avctx->get_buffer(avctx, p) < 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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p->key_frame = 1; |
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l->bitbuf = 0; |
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l->bits = 0; |
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l->buf = buf + 8; |
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if (buf[2] >> 4 == 6) |
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l->shift = 2; |
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else { |
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l->shift = 8 - (buf[2] >> 4); |
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if (l->shift > 4) { |
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av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); |
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l->shift = 4; |
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} |
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if (l->shift < 1) { |
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av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); |
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l->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(l, prev_y); |
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prev_u = U[i] = wnv1_get_code(l, prev_u); |
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prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]); |
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prev_v = V[i] = wnv1_get_code(l, 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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*data_size = sizeof(AVFrame); |
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*(AVFrame*)data = l->pic; |
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return buf_size; |
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} |
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static int decode_init(AVCodecContext *avctx){ |
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WNV1Context * const l = avctx->priv_data; |
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l->avctx = avctx; |
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avctx->pix_fmt = PIX_FMT_YUV422P; |
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return 0; |
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} |
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AVCodec wnv1_decoder = { |
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"wnv1", |
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CODEC_TYPE_VIDEO, |
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CODEC_ID_WNV1, |
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sizeof(WNV1Context), |
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decode_init, |
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NULL, |
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NULL, |
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decode_frame, |
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CODEC_CAP_DR1, |
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}; |
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