1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... parser
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 libavcodec/h264_parser.c
24 * H.264 / AVC / MPEG4 part10 parser.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#include "parser.h"
29#include "h264_parser.h"
30#include "h264data.h"
31#include "golomb.h"
32
33#include <assert.h>
34
35
36int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
37{
38    int i;
39    uint32_t state;
40    ParseContext *pc = &(h->s.parse_context);
41//printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
42//    mb_addr= pc->mb_addr - 1;
43    state= pc->state;
44    if(state>13)
45        state= 7;
46
47    for(i=0; i<buf_size; i++){
48        if(state==7){
49#if HAVE_FAST_UNALIGNED
50        /* we check i<buf_size instead of i+3/7 because its simpler
51         * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
52         */
53#    if HAVE_FAST_64BIT
54            while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
55                i+=8;
56#    else
57            while(i<buf_size && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
58                i+=4;
59#    endif
60#endif
61            for(; i<buf_size; i++){
62                if(!buf[i]){
63                    state=2;
64                    break;
65                }
66            }
67        }else if(state<=2){
68            if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
69            else if(buf[i]) state = 7;
70            else            state>>=1; //2->1, 1->0, 0->0
71        }else if(state<=5){
72            int v= buf[i] & 0x1F;
73            if(v==7 || v==8 || v==9){
74                if(pc->frame_start_found){
75                    i++;
76                    goto found;
77                }
78            }else if(v==1 || v==2 || v==5){
79                if(pc->frame_start_found){
80                    state+=8;
81                    continue;
82                }else
83                    pc->frame_start_found = 1;
84            }
85            state= 7;
86        }else{
87            if(buf[i] & 0x80)
88                goto found;
89            state= 7;
90        }
91    }
92    pc->state= state;
93    return END_NOT_FOUND;
94
95found:
96    pc->state=7;
97    pc->frame_start_found= 0;
98    return i-(state&5);
99}
100
101/*!
102 * Parse NAL units of found picture and decode some basic information.
103 *
104 * @param s parser context.
105 * @param avctx codec context.
106 * @param buf buffer with field/frame data.
107 * @param buf_size size of the buffer.
108 */
109static inline int parse_nal_units(AVCodecParserContext *s,
110                                  AVCodecContext *avctx,
111                                  const uint8_t *buf, int buf_size)
112{
113    H264Context *h = s->priv_data;
114    const uint8_t *buf_end = buf + buf_size;
115    unsigned int pps_id;
116    unsigned int slice_type;
117    int state;
118    const uint8_t *ptr;
119
120    /* set some sane default values */
121    s->pict_type = FF_I_TYPE;
122    s->key_frame = 0;
123
124    h->s.avctx= avctx;
125    h->sei_recovery_frame_cnt = -1;
126    h->sei_dpb_output_delay         =  0;
127    h->sei_cpb_removal_delay        = -1;
128    h->sei_buffering_period_present =  0;
129
130    for(;;) {
131        int src_length, dst_length, consumed;
132        buf = ff_find_start_code(buf, buf_end, &state);
133        if(buf >= buf_end)
134            break;
135        --buf;
136        src_length = buf_end - buf;
137        switch (state & 0x1f) {
138        case NAL_SLICE:
139        case NAL_IDR_SLICE:
140            // Do not walk the whole buffer just to decode slice header
141            if (src_length > 20)
142                src_length = 20;
143            break;
144        }
145        ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
146        if (ptr==NULL || dst_length < 0)
147            break;
148
149        init_get_bits(&h->s.gb, ptr, 8*dst_length);
150        switch(h->nal_unit_type) {
151        case NAL_SPS:
152            ff_h264_decode_seq_parameter_set(h);
153            break;
154        case NAL_PPS:
155            ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
156            break;
157        case NAL_SEI:
158            ff_h264_decode_sei(h);
159            break;
160        case NAL_IDR_SLICE:
161            s->key_frame = 1;
162            /* fall through */
163        case NAL_SLICE:
164            get_ue_golomb(&h->s.gb);  // skip first_mb_in_slice
165            slice_type = get_ue_golomb_31(&h->s.gb);
166            s->pict_type = golomb_to_pict_type[slice_type % 5];
167            if (h->sei_recovery_frame_cnt >= 0) {
168                /* key frame, since recovery_frame_cnt is set */
169                s->key_frame = 1;
170            }
171            pps_id= get_ue_golomb(&h->s.gb);
172            if(pps_id>=MAX_PPS_COUNT) {
173                av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
174                return -1;
175            }
176            if(!h->pps_buffers[pps_id]) {
177                av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
178                return -1;
179            }
180            h->pps= *h->pps_buffers[pps_id];
181            if(!h->sps_buffers[h->pps.sps_id]) {
182                av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
183                return -1;
184            }
185            h->sps = *h->sps_buffers[h->pps.sps_id];
186            h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
187
188            if(h->sps.frame_mbs_only_flag){
189                h->s.picture_structure= PICT_FRAME;
190            }else{
191                if(get_bits1(&h->s.gb)) { //field_pic_flag
192                    h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
193                } else {
194                    h->s.picture_structure= PICT_FRAME;
195                }
196            }
197
198            if(h->sps.pic_struct_present_flag) {
199                switch (h->sei_pic_struct) {
200                    case SEI_PIC_STRUCT_TOP_FIELD:
201                    case SEI_PIC_STRUCT_BOTTOM_FIELD:
202                        s->repeat_pict = 0;
203                        break;
204                    case SEI_PIC_STRUCT_FRAME:
205                    case SEI_PIC_STRUCT_TOP_BOTTOM:
206                    case SEI_PIC_STRUCT_BOTTOM_TOP:
207                        s->repeat_pict = 1;
208                        break;
209                    case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
210                    case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
211                        s->repeat_pict = 2;
212                        break;
213                    case SEI_PIC_STRUCT_FRAME_DOUBLING:
214                        s->repeat_pict = 3;
215                        break;
216                    case SEI_PIC_STRUCT_FRAME_TRIPLING:
217                        s->repeat_pict = 5;
218                        break;
219                    default:
220                        s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
221                        break;
222                }
223            } else {
224                s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
225            }
226
227            return 0; /* no need to evaluate the rest */
228        }
229        buf += consumed;
230    }
231    /* didn't find a picture! */
232    av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit\n");
233    return -1;
234}
235
236static int h264_parse(AVCodecParserContext *s,
237                      AVCodecContext *avctx,
238                      const uint8_t **poutbuf, int *poutbuf_size,
239                      const uint8_t *buf, int buf_size)
240{
241    H264Context *h = s->priv_data;
242    ParseContext *pc = &h->s.parse_context;
243    int next;
244
245    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
246        next= buf_size;
247    }else{
248        next= ff_h264_find_frame_end(h, buf, buf_size);
249
250        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
251            *poutbuf = NULL;
252            *poutbuf_size = 0;
253            return buf_size;
254        }
255
256        if(next<0 && next != END_NOT_FOUND){
257            assert(pc->last_index + next >= 0 );
258            ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
259        }
260
261        parse_nal_units(s, avctx, buf, buf_size);
262
263        if (h->sei_cpb_removal_delay >= 0) {
264            s->dts_sync_point    = h->sei_buffering_period_present;
265            s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
266            s->pts_dts_delta     = h->sei_dpb_output_delay;
267        } else {
268            s->dts_sync_point    = INT_MIN;
269            s->dts_ref_dts_delta = INT_MIN;
270            s->pts_dts_delta     = INT_MIN;
271        }
272    }
273
274    *poutbuf = buf;
275    *poutbuf_size = buf_size;
276    return next;
277}
278
279static int h264_split(AVCodecContext *avctx,
280                      const uint8_t *buf, int buf_size)
281{
282    int i;
283    uint32_t state = -1;
284    int has_sps= 0;
285
286    for(i=0; i<=buf_size; i++){
287        if((state&0xFFFFFF1F) == 0x107)
288            has_sps=1;
289/*        if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
290        }*/
291        if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
292            if(has_sps){
293                while(i>4 && buf[i-5]==0) i--;
294                return i-4;
295            }
296        }
297        if (i<buf_size)
298            state= (state<<8) | buf[i];
299    }
300    return 0;
301}
302
303static void close(AVCodecParserContext *s)
304{
305    H264Context *h = s->priv_data;
306    ParseContext *pc = &h->s.parse_context;
307
308    av_free(pc->buffer);
309}
310
311
312AVCodecParser h264_parser = {
313    { CODEC_ID_H264 },
314    sizeof(H264Context),
315    NULL,
316    h264_parse,
317    close,
318    h264_split,
319};
320