1/*
2 * HEVC Annex B format parser
3 *
4 * Copyright (C) 2012 - 2013 Guillaume Martres
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "libavutil/common.h"
24
25#include "parser.h"
26#include "hevc.h"
27#include "golomb.h"
28
29#define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
30
31typedef struct HEVCParseContext {
32    HEVCContext  h;
33    ParseContext pc;
34} HEVCParseContext;
35
36/**
37 * Find the end of the current frame in the bitstream.
38 * @return the position of the first byte of the next frame, or END_NOT_FOUND
39 */
40static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
41                               int buf_size)
42{
43    int i;
44    ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
45
46    for (i = 0; i < buf_size; i++) {
47        int nut;
48
49        pc->state64 = (pc->state64 << 8) | buf[i];
50
51        if (((pc->state64 >> 3 * 8) & 0xFFFFFF) != START_CODE)
52            continue;
53
54        nut = (pc->state64 >> 2 * 8 + 1) & 0x3F;
55        // Beginning of access unit
56        if ((nut >= NAL_VPS && nut <= NAL_AUD) || nut == NAL_SEI_PREFIX ||
57            (nut >= 41 && nut <= 44) || (nut >= 48 && nut <= 55)) {
58            if (pc->frame_start_found) {
59                pc->frame_start_found = 0;
60                return i - 5;
61            }
62        } else if (nut <= NAL_RASL_R ||
63                   (nut >= NAL_BLA_W_LP && nut <= NAL_CRA_NUT)) {
64            int first_slice_segment_in_pic_flag = buf[i] >> 7;
65            if (first_slice_segment_in_pic_flag) {
66                if (!pc->frame_start_found) {
67                    pc->frame_start_found = 1;
68                } else { // First slice of next frame found
69                    pc->frame_start_found = 0;
70                    return i - 5;
71                }
72            }
73        }
74    }
75
76    return END_NOT_FOUND;
77}
78
79/**
80 * Parse NAL units of found picture and decode some basic information.
81 *
82 * @param s parser context.
83 * @param avctx codec context.
84 * @param buf buffer with field/frame data.
85 * @param buf_size size of the buffer.
86 */
87static inline int parse_nal_units(AVCodecParserContext *s, AVCodecContext *avctx,
88                      const uint8_t *buf, int buf_size)
89{
90    HEVCContext   *h  = &((HEVCParseContext *)s->priv_data)->h;
91    GetBitContext *gb = &h->HEVClc->gb;
92    SliceHeader   *sh = &h->sh;
93    const uint8_t *buf_end = buf + buf_size;
94    int state = -1, i;
95    HEVCNAL *nal;
96
97    /* set some sane default values */
98    s->pict_type         = AV_PICTURE_TYPE_I;
99    s->key_frame         = 0;
100    s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
101
102    h->avctx = avctx;
103
104    if (!buf_size)
105        return 0;
106
107    if (h->nals_allocated < 1) {
108        HEVCNAL *tmp = av_realloc_array(h->nals, 1, sizeof(*tmp));
109        if (!tmp)
110            return AVERROR(ENOMEM);
111        h->nals = tmp;
112        memset(h->nals, 0, sizeof(*tmp));
113        h->nals_allocated = 1;
114    }
115
116    nal = &h->nals[0];
117
118    for (;;) {
119        int src_length, consumed;
120        buf = avpriv_find_start_code(buf, buf_end, &state);
121        if (--buf + 2 >= buf_end)
122            break;
123        src_length = buf_end - buf;
124
125        h->nal_unit_type = (*buf >> 1) & 0x3f;
126        h->temporal_id   = (*(buf + 1) & 0x07) - 1;
127        if (h->nal_unit_type <= NAL_CRA_NUT) {
128            // Do not walk the whole buffer just to decode slice segment header
129            if (src_length > 20)
130                src_length = 20;
131        }
132
133        consumed = ff_hevc_extract_rbsp(h, buf, src_length, nal);
134        if (consumed < 0)
135            return consumed;
136
137        init_get_bits8(gb, nal->data + 2, nal->size);
138        switch (h->nal_unit_type) {
139        case NAL_VPS:
140            ff_hevc_decode_nal_vps(h);
141            break;
142        case NAL_SPS:
143            ff_hevc_decode_nal_sps(h);
144            break;
145        case NAL_PPS:
146            ff_hevc_decode_nal_pps(h);
147            break;
148        case NAL_SEI_PREFIX:
149        case NAL_SEI_SUFFIX:
150            ff_hevc_decode_nal_sei(h);
151            break;
152        case NAL_TRAIL_N:
153        case NAL_TRAIL_R:
154        case NAL_TSA_N:
155        case NAL_TSA_R:
156        case NAL_STSA_N:
157        case NAL_STSA_R:
158        case NAL_RADL_N:
159        case NAL_RADL_R:
160        case NAL_RASL_N:
161        case NAL_RASL_R:
162        case NAL_BLA_W_LP:
163        case NAL_BLA_W_RADL:
164        case NAL_BLA_N_LP:
165        case NAL_IDR_W_RADL:
166        case NAL_IDR_N_LP:
167        case NAL_CRA_NUT:
168            sh->first_slice_in_pic_flag = get_bits1(gb);
169            s->picture_structure = h->picture_struct;
170            s->field_order = h->picture_struct;
171
172            if (IS_IRAP(h)) {
173                s->key_frame = 1;
174                sh->no_output_of_prior_pics_flag = get_bits1(gb);
175            }
176
177            sh->pps_id = get_ue_golomb(gb);
178            if (sh->pps_id >= MAX_PPS_COUNT || !h->pps_list[sh->pps_id]) {
179                av_log(h->avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
180                return AVERROR_INVALIDDATA;
181            }
182            h->pps = (HEVCPPS*)h->pps_list[sh->pps_id]->data;
183
184            if (h->pps->sps_id >= MAX_SPS_COUNT || !h->sps_list[h->pps->sps_id]) {
185                av_log(h->avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", h->pps->sps_id);
186                return AVERROR_INVALIDDATA;
187            }
188            if (h->sps != (HEVCSPS*)h->sps_list[h->pps->sps_id]->data) {
189                h->sps = (HEVCSPS*)h->sps_list[h->pps->sps_id]->data;
190                h->vps = (HEVCVPS*)h->vps_list[h->sps->vps_id]->data;
191            }
192
193            if (!sh->first_slice_in_pic_flag) {
194                int slice_address_length;
195
196                if (h->pps->dependent_slice_segments_enabled_flag)
197                    sh->dependent_slice_segment_flag = get_bits1(gb);
198                else
199                    sh->dependent_slice_segment_flag = 0;
200
201                slice_address_length = av_ceil_log2_c(h->sps->ctb_width *
202                                                      h->sps->ctb_height);
203                sh->slice_segment_addr = get_bits(gb, slice_address_length);
204                if (sh->slice_segment_addr >= h->sps->ctb_width * h->sps->ctb_height) {
205                    av_log(h->avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
206                           sh->slice_segment_addr);
207                    return AVERROR_INVALIDDATA;
208                }
209            } else
210                sh->dependent_slice_segment_flag = 0;
211
212            if (sh->dependent_slice_segment_flag)
213                break;
214
215            for (i = 0; i < h->pps->num_extra_slice_header_bits; i++)
216                skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
217
218            sh->slice_type = get_ue_golomb(gb);
219            if (!(sh->slice_type == I_SLICE || sh->slice_type == P_SLICE ||
220                  sh->slice_type == B_SLICE)) {
221                av_log(h->avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
222                       sh->slice_type);
223                return AVERROR_INVALIDDATA;
224            }
225            s->pict_type = sh->slice_type == B_SLICE ? AV_PICTURE_TYPE_B :
226                           sh->slice_type == P_SLICE ? AV_PICTURE_TYPE_P :
227                                                       AV_PICTURE_TYPE_I;
228
229            if (h->pps->output_flag_present_flag)
230                sh->pic_output_flag = get_bits1(gb);
231
232            if (h->sps->separate_colour_plane_flag)
233                sh->colour_plane_id = get_bits(gb, 2);
234
235            if (!IS_IDR(h)) {
236                sh->pic_order_cnt_lsb = get_bits(gb, h->sps->log2_max_poc_lsb);
237                s->output_picture_number = h->poc = ff_hevc_compute_poc(h, sh->pic_order_cnt_lsb);
238            } else
239                s->output_picture_number = h->poc = 0;
240
241            if (h->temporal_id == 0 &&
242                h->nal_unit_type != NAL_TRAIL_N &&
243                h->nal_unit_type != NAL_TSA_N &&
244                h->nal_unit_type != NAL_STSA_N &&
245                h->nal_unit_type != NAL_RADL_N &&
246                h->nal_unit_type != NAL_RASL_N &&
247                h->nal_unit_type != NAL_RADL_R &&
248                h->nal_unit_type != NAL_RASL_R)
249                h->pocTid0 = h->poc;
250
251            return 0; /* no need to evaluate the rest */
252        }
253        buf += consumed;
254    }
255    /* didn't find a picture! */
256    av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
257    return -1;
258}
259
260static int hevc_parse(AVCodecParserContext *s,
261                      AVCodecContext *avctx,
262                      const uint8_t **poutbuf, int *poutbuf_size,
263                      const uint8_t *buf, int buf_size)
264{
265    int next;
266    ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
267
268    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
269        next = buf_size;
270    } else {
271        next = hevc_find_frame_end(s, buf, buf_size);
272        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
273            *poutbuf      = NULL;
274            *poutbuf_size = 0;
275            return buf_size;
276        }
277    }
278
279    parse_nal_units(s, avctx, buf, buf_size);
280
281    *poutbuf      = buf;
282    *poutbuf_size = buf_size;
283    return next;
284}
285
286// Split after the parameter sets at the beginning of the stream if they exist.
287static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
288{
289    int i;
290    uint32_t state = -1;
291    int has_ps = 0;
292
293    for (i = 0; i < buf_size; i++) {
294        state = (state << 8) | buf[i];
295        if (((state >> 8) & 0xFFFFFF) == START_CODE) {
296            int nut = (state >> 1) & 0x3F;
297            if (nut >= NAL_VPS && nut <= NAL_PPS)
298                has_ps = 1;
299            else if (has_ps)
300                return i - 3;
301            else // no parameter set at the beginning of the stream
302                return 0;
303        }
304    }
305    return 0;
306}
307
308static int hevc_init(AVCodecParserContext *s)
309{
310    HEVCContext  *h  = &((HEVCParseContext *)s->priv_data)->h;
311    h->HEVClc = av_mallocz(sizeof(HEVCLocalContext));
312    h->skipped_bytes_pos_size = INT_MAX;
313
314    return 0;
315}
316
317static void hevc_close(AVCodecParserContext *s)
318{
319    int i;
320    HEVCContext  *h  = &((HEVCParseContext *)s->priv_data)->h;
321    ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
322
323    av_freep(&h->skipped_bytes_pos);
324    av_freep(&h->HEVClc);
325    av_freep(&pc->buffer);
326
327    for (i = 0; i < FF_ARRAY_ELEMS(h->vps_list); i++)
328        av_buffer_unref(&h->vps_list[i]);
329    for (i = 0; i < FF_ARRAY_ELEMS(h->sps_list); i++)
330        av_buffer_unref(&h->sps_list[i]);
331    for (i = 0; i < FF_ARRAY_ELEMS(h->pps_list); i++)
332        av_buffer_unref(&h->pps_list[i]);
333
334    av_buffer_unref(&h->current_sps);
335    h->sps = NULL;
336
337    for (i = 0; i < h->nals_allocated; i++)
338        av_freep(&h->nals[i].rbsp_buffer);
339    av_freep(&h->nals);
340    h->nals_allocated = 0;
341}
342
343AVCodecParser ff_hevc_parser = {
344    .codec_ids      = { AV_CODEC_ID_HEVC },
345    .priv_data_size = sizeof(HEVCParseContext),
346    .parser_init    = hevc_init,
347    .parser_parse   = hevc_parse,
348    .parser_close   = hevc_close,
349    .split          = hevc_split,
350};
351