mpeg12: do not decode extradata more than once.
[libav.git] / libavcodec / mpeg12.h
1 /*
2 * MPEG1/2 common code
3 * Copyright (c) 2007 Aurelien Jacobs <aurel@gnuage.org>
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #ifndef AVCODEC_MPEG12_H
23 #define AVCODEC_MPEG12_H
24
25 #include "mpegvideo.h"
26
27 #define DC_VLC_BITS 9
28 #define TEX_VLC_BITS 9
29
30 extern VLC ff_dc_lum_vlc;
31 extern VLC ff_dc_chroma_vlc;
32
33 typedef struct Mpeg1Context {
34 MpegEncContext mpeg_enc_ctx;
35 int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
36 int repeat_field; /* true if we must repeat the field */
37 AVPanScan pan_scan; /**< some temporary storage for the panscan */
38 int slice_count;
39 int swap_uv;//indicate VCR2
40 int save_aspect_info;
41 int save_width, save_height, save_progressive_seq;
42 AVRational frame_rate_ext; ///< MPEG-2 specific framerate modificator
43 int sync; ///< Did we reach a sync point like a GOP/SEQ/KEYFrame?
44 int closed_gop; ///< GOP is closed
45 int extradata_decoded;
46 } Mpeg1Context;
47
48 extern uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
49
50 void ff_mpeg12_common_init(MpegEncContext *s);
51 void ff_mpeg12_init_vlcs(void);
52
53 static inline int decode_dc(GetBitContext *gb, int component)
54 {
55 int code, diff;
56
57 if (component == 0) {
58 code = get_vlc2(gb, ff_dc_lum_vlc.table, DC_VLC_BITS, 2);
59 } else {
60 code = get_vlc2(gb, ff_dc_chroma_vlc.table, DC_VLC_BITS, 2);
61 }
62 if (code < 0){
63 av_log(NULL, AV_LOG_ERROR, "invalid dc code at\n");
64 return 0xffff;
65 }
66 if (code == 0) {
67 diff = 0;
68 } else {
69 diff = get_xbits(gb, code);
70 }
71 return diff;
72 }
73
74 extern int ff_mpeg1_decode_block_intra(MpegEncContext *s, DCTELEM *block, int n);
75
76 #endif /* AVCODEC_MPEG12_H */