1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... sei decoding
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * H.264 / AVC / MPEG4 part10 sei decoding.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#include "internal.h"
29#include "avcodec.h"
30#include "h264.h"
31#include "golomb.h"
32
33//#undef NDEBUG
34#include <assert.h>
35
36static const uint8_t sei_num_clock_ts_table[9]={
37    1,  1,  1,  2,  2,  3,  3,  2,  3
38};
39
40void ff_h264_reset_sei(H264Context *h) {
41    h->sei_recovery_frame_cnt       = -1;
42    h->sei_dpb_output_delay         =  0;
43    h->sei_cpb_removal_delay        = -1;
44    h->sei_buffering_period_present =  0;
45}
46
47static int decode_picture_timing(H264Context *h){
48    MpegEncContext * const s = &h->s;
49    if(h->sps.nal_hrd_parameters_present_flag || h->sps.vcl_hrd_parameters_present_flag){
50        h->sei_cpb_removal_delay = get_bits(&s->gb, h->sps.cpb_removal_delay_length);
51        h->sei_dpb_output_delay = get_bits(&s->gb, h->sps.dpb_output_delay_length);
52    }
53    if(h->sps.pic_struct_present_flag){
54        unsigned int i, num_clock_ts;
55        h->sei_pic_struct = get_bits(&s->gb, 4);
56        h->sei_ct_type    = 0;
57
58        if (h->sei_pic_struct > SEI_PIC_STRUCT_FRAME_TRIPLING)
59            return -1;
60
61        num_clock_ts = sei_num_clock_ts_table[h->sei_pic_struct];
62
63        for (i = 0 ; i < num_clock_ts ; i++){
64            if(get_bits(&s->gb, 1)){                  /* clock_timestamp_flag */
65                unsigned int full_timestamp_flag;
66                h->sei_ct_type |= 1<<get_bits(&s->gb, 2);
67                skip_bits(&s->gb, 1);                 /* nuit_field_based_flag */
68                skip_bits(&s->gb, 5);                 /* counting_type */
69                full_timestamp_flag = get_bits(&s->gb, 1);
70                skip_bits(&s->gb, 1);                 /* discontinuity_flag */
71                skip_bits(&s->gb, 1);                 /* cnt_dropped_flag */
72                skip_bits(&s->gb, 8);                 /* n_frames */
73                if(full_timestamp_flag){
74                    skip_bits(&s->gb, 6);             /* seconds_value 0..59 */
75                    skip_bits(&s->gb, 6);             /* minutes_value 0..59 */
76                    skip_bits(&s->gb, 5);             /* hours_value 0..23 */
77                }else{
78                    if(get_bits(&s->gb, 1)){          /* seconds_flag */
79                        skip_bits(&s->gb, 6);         /* seconds_value range 0..59 */
80                        if(get_bits(&s->gb, 1)){      /* minutes_flag */
81                            skip_bits(&s->gb, 6);     /* minutes_value 0..59 */
82                            if(get_bits(&s->gb, 1))   /* hours_flag */
83                                skip_bits(&s->gb, 5); /* hours_value 0..23 */
84                        }
85                    }
86                }
87                if(h->sps.time_offset_length > 0)
88                    skip_bits(&s->gb, h->sps.time_offset_length); /* time_offset */
89            }
90        }
91
92        if(s->avctx->debug & FF_DEBUG_PICT_INFO)
93            av_log(s->avctx, AV_LOG_DEBUG, "ct_type:%X pic_struct:%d\n", h->sei_ct_type, h->sei_pic_struct);
94    }
95    return 0;
96}
97
98static int decode_unregistered_user_data(H264Context *h, int size){
99    MpegEncContext * const s = &h->s;
100    uint8_t user_data[16+256];
101    int e, build, i;
102
103    if(size<16)
104        return -1;
105
106    for(i=0; i<sizeof(user_data)-1 && i<size; i++){
107        user_data[i]= get_bits(&s->gb, 8);
108    }
109
110    user_data[i]= 0;
111    e= sscanf(user_data+16, "x264 - core %d"/*%s - H.264/MPEG-4 AVC codec - Copyleft 2005 - http://www.videolan.org/x264.html*/, &build);
112    if(e==1 && build>0)
113        h->x264_build= build;
114
115    if(s->avctx->debug & FF_DEBUG_BUGS)
116        av_log(s->avctx, AV_LOG_DEBUG, "user data:\"%s\"\n", user_data+16);
117
118    for(; i<size; i++)
119        skip_bits(&s->gb, 8);
120
121    return 0;
122}
123
124static int decode_recovery_point(H264Context *h){
125    MpegEncContext * const s = &h->s;
126
127    h->sei_recovery_frame_cnt = get_ue_golomb(&s->gb);
128    skip_bits(&s->gb, 4);       /* 1b exact_match_flag, 1b broken_link_flag, 2b changing_slice_group_idc */
129
130    return 0;
131}
132
133static int decode_buffering_period(H264Context *h){
134    MpegEncContext * const s = &h->s;
135    unsigned int sps_id;
136    int sched_sel_idx;
137    SPS *sps;
138
139    sps_id = get_ue_golomb_31(&s->gb);
140    if(sps_id > 31 || !h->sps_buffers[sps_id]) {
141        av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS %d referenced in buffering period\n", sps_id);
142        return -1;
143    }
144    sps = h->sps_buffers[sps_id];
145
146    // NOTE: This is really so duplicated in the standard... See H.264, D.1.1
147    if (sps->nal_hrd_parameters_present_flag) {
148        for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) {
149            h->initial_cpb_removal_delay[sched_sel_idx] = get_bits(&s->gb, sps->initial_cpb_removal_delay_length);
150            skip_bits(&s->gb, sps->initial_cpb_removal_delay_length); // initial_cpb_removal_delay_offset
151        }
152    }
153    if (sps->vcl_hrd_parameters_present_flag) {
154        for (sched_sel_idx = 0; sched_sel_idx < sps->cpb_cnt; sched_sel_idx++) {
155            h->initial_cpb_removal_delay[sched_sel_idx] = get_bits(&s->gb, sps->initial_cpb_removal_delay_length);
156            skip_bits(&s->gb, sps->initial_cpb_removal_delay_length); // initial_cpb_removal_delay_offset
157        }
158    }
159
160    h->sei_buffering_period_present = 1;
161    return 0;
162}
163
164int ff_h264_decode_sei(H264Context *h){
165    MpegEncContext * const s = &h->s;
166
167    while(get_bits_count(&s->gb) + 16 < s->gb.size_in_bits){
168        int size, type;
169
170        type=0;
171        do{
172            type+= show_bits(&s->gb, 8);
173        }while(get_bits(&s->gb, 8) == 255);
174
175        size=0;
176        do{
177            size+= show_bits(&s->gb, 8);
178        }while(get_bits(&s->gb, 8) == 255);
179
180        switch(type){
181        case SEI_TYPE_PIC_TIMING: // Picture timing SEI
182            if(decode_picture_timing(h) < 0)
183                return -1;
184            break;
185        case SEI_TYPE_USER_DATA_UNREGISTERED:
186            if(decode_unregistered_user_data(h, size) < 0)
187                return -1;
188            break;
189        case SEI_TYPE_RECOVERY_POINT:
190            if(decode_recovery_point(h) < 0)
191                return -1;
192            break;
193        case SEI_BUFFERING_PERIOD:
194            if(decode_buffering_period(h) < 0)
195                return -1;
196            break;
197        default:
198            skip_bits(&s->gb, 8*size);
199        }
200
201        //FIXME check bits here
202        align_get_bits(&s->gb);
203    }
204
205    return 0;
206}
207