/* * Winnov WNV1 codec * Copyright (c) 2005 Konstantin Shishkov * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Winnov WNV1 codec. */ #include "avcodec.h" #include "get_bits.h" #include "libavutil/common.h" typedef struct WNV1Context{ AVCodecContext *avctx; AVFrame pic; int shift; GetBitContext gb; } WNV1Context; static const uint16_t code_tab[16][2]={ {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3}, {0x000,1}, {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8} }; #define CODE_VLC_BITS 9 static VLC code_vlc; /* returns modified base_value */ static inline int wnv1_get_code(WNV1Context *w, int base_value) { int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); if(v==15) return av_reverse[ get_bits(&w->gb, 8 - w->shift) ]; else return base_value + ((v - 7)<<w->shift); } static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; WNV1Context * const l = avctx->priv_data; AVFrame * const p = &l->pic; unsigned char *Y,*U,*V; int i, j; int prev_y = 0, prev_u = 0, prev_v = 0; uint8_t *rbuf; if(buf_size<=8) { av_log(avctx, AV_LOG_ERROR, "buf_size %d is too small\n", buf_size); return AVERROR_INVALIDDATA; } rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); if(!rbuf){ av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n"); return -1; } if(p->data[0]) avctx->release_buffer(avctx, p); p->reference = 0; if(avctx->get_buffer(avctx, p) < 0){ av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); av_free(rbuf); return -1; } p->key_frame = 1; for(i=8; i<buf_size; i++) rbuf[i]= av_reverse[ buf[i] ]; init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8); if (buf[2] >> 4 == 6) l->shift = 2; else { l->shift = 8 - (buf[2] >> 4); if (l->shift > 4) { av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n", buf[2] >> 4); l->shift = 4; } if (l->shift < 1) { av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n", buf[2] >> 4); l->shift = 1; } } Y = p->data[0]; U = p->data[1]; V = p->data[2]; for (j = 0; j < avctx->height; j++) { for (i = 0; i < avctx->width / 2; i++) { Y[i * 2] = wnv1_get_code(l, prev_y); prev_u = U[i] = wnv1_get_code(l, prev_u); prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]); prev_v = V[i] = wnv1_get_code(l, prev_v); } Y += p->linesize[0]; U += p->linesize[1]; V += p->linesize[2]; } *data_size = sizeof(AVFrame); *(AVFrame*)data = l->pic; av_free(rbuf); return buf_size; } static av_cold int decode_init(AVCodecContext *avctx){ WNV1Context * const l = avctx->priv_data; static VLC_TYPE code_table[1 << CODE_VLC_BITS][2]; l->avctx = avctx; avctx->pix_fmt = PIX_FMT_YUV422P; avcodec_get_frame_defaults(&l->pic); code_vlc.table = code_table; code_vlc.table_allocated = 1 << CODE_VLC_BITS; init_vlc(&code_vlc, CODE_VLC_BITS, 16, &code_tab[0][1], 4, 2, &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC); return 0; } static av_cold int decode_end(AVCodecContext *avctx){ WNV1Context * const l = avctx->priv_data; AVFrame *pic = &l->pic; if (pic->data[0]) avctx->release_buffer(avctx, pic); return 0; } AVCodec ff_wnv1_decoder = { .name = "wnv1", .type = AVMEDIA_TYPE_VIDEO, .id = CODEC_ID_WNV1, .priv_data_size = sizeof(WNV1Context), .init = decode_init, .close = decode_end, .decode = decode_frame, .capabilities = CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), };