2 * HEVC Annex B format parser
4 * Copyright (C) 2012 - 2013 Guillaume Martres
6 * This file is part of FFmpeg.
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.
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.
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
23 #include "libavutil/common.h"
29 #define START_CODE 0x000001 ///< start_code_prefix_one_3bytes
31 typedef struct HEVCParseContext {
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
40 static int hevc_find_frame_end(AVCodecParserContext *s, const uint8_t *buf,
44 ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
46 for (i = 0; i < buf_size; i++) {
49 pc->state64 = (pc->state64 << 8) | buf[i];
51 if (((pc->state64 >> 3 * 8) & 0xFFFFFF) != START_CODE)
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;
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;
80 * Parse NAL units of found picture and decode some basic information.
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.
87 static inline int parse_nal_units(AVCodecParserContext *s, AVCodecContext *avctx,
88 const uint8_t *buf, int buf_size)
90 HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
91 GetBitContext *gb = &h->HEVClc->gb;
92 SliceHeader *sh = &h->sh;
93 HEVCParamSets *ps = &h->ps;
94 HEVCPacket *pkt = &h->pkt;
95 const uint8_t *buf_end = buf + buf_size;
99 /* set some sane default values */
100 s->pict_type = AV_PICTURE_TYPE_I;
102 s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
109 if (pkt->nals_allocated < 1) {
110 HEVCNAL *tmp = av_realloc_array(pkt->nals, 1, sizeof(*tmp));
112 return AVERROR(ENOMEM);
114 memset(pkt->nals, 0, sizeof(*tmp));
115 pkt->nals_allocated = 1;
121 int src_length, consumed;
122 buf = avpriv_find_start_code(buf, buf_end, &state);
123 if (--buf + 2 >= buf_end)
125 src_length = buf_end - buf;
127 h->nal_unit_type = (*buf >> 1) & 0x3f;
128 h->temporal_id = (*(buf + 1) & 0x07) - 1;
129 if (h->nal_unit_type <= NAL_CRA_NUT) {
130 // Do not walk the whole buffer just to decode slice segment header
135 consumed = ff_hevc_extract_rbsp(h, buf, src_length, nal);
139 init_get_bits8(gb, nal->data + 2, nal->size);
140 switch (h->nal_unit_type) {
142 ff_hevc_decode_nal_vps(gb, avctx, ps);
145 ff_hevc_decode_nal_sps(gb, avctx, ps, h->apply_defdispwin);
148 ff_hevc_decode_nal_pps(gb, avctx, ps);
152 ff_hevc_decode_nal_sei(h);
170 sh->first_slice_in_pic_flag = get_bits1(gb);
171 s->picture_structure = h->picture_struct;
172 s->field_order = h->picture_struct;
176 sh->no_output_of_prior_pics_flag = get_bits1(gb);
179 sh->pps_id = get_ue_golomb(gb);
180 if (sh->pps_id >= MAX_PPS_COUNT || !ps->pps_list[sh->pps_id]) {
181 av_log(h->avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
182 return AVERROR_INVALIDDATA;
184 ps->pps = (HEVCPPS*)ps->pps_list[sh->pps_id]->data;
186 if (ps->pps->sps_id >= MAX_SPS_COUNT || !ps->sps_list[ps->pps->sps_id]) {
187 av_log(h->avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", ps->pps->sps_id);
188 return AVERROR_INVALIDDATA;
190 if (ps->sps != (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data) {
191 ps->sps = (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data;
192 ps->vps = (HEVCVPS*)ps->vps_list[ps->sps->vps_id]->data;
195 if (!sh->first_slice_in_pic_flag) {
196 int slice_address_length;
198 if (ps->pps->dependent_slice_segments_enabled_flag)
199 sh->dependent_slice_segment_flag = get_bits1(gb);
201 sh->dependent_slice_segment_flag = 0;
203 slice_address_length = av_ceil_log2_c(ps->sps->ctb_width *
204 ps->sps->ctb_height);
205 sh->slice_segment_addr = slice_address_length ? get_bits(gb, slice_address_length) : 0;
206 if (sh->slice_segment_addr >= ps->sps->ctb_width * ps->sps->ctb_height) {
207 av_log(h->avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
208 sh->slice_segment_addr);
209 return AVERROR_INVALIDDATA;
212 sh->dependent_slice_segment_flag = 0;
214 if (sh->dependent_slice_segment_flag)
217 for (i = 0; i < ps->pps->num_extra_slice_header_bits; i++)
218 skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
220 sh->slice_type = get_ue_golomb(gb);
221 if (!(sh->slice_type == I_SLICE || sh->slice_type == P_SLICE ||
222 sh->slice_type == B_SLICE)) {
223 av_log(h->avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
225 return AVERROR_INVALIDDATA;
227 s->pict_type = sh->slice_type == B_SLICE ? AV_PICTURE_TYPE_B :
228 sh->slice_type == P_SLICE ? AV_PICTURE_TYPE_P :
231 if (ps->pps->output_flag_present_flag)
232 sh->pic_output_flag = get_bits1(gb);
234 if (ps->sps->separate_colour_plane_flag)
235 sh->colour_plane_id = get_bits(gb, 2);
238 sh->pic_order_cnt_lsb = get_bits(gb, ps->sps->log2_max_poc_lsb);
239 s->output_picture_number = h->poc = ff_hevc_compute_poc(h, sh->pic_order_cnt_lsb);
241 s->output_picture_number = h->poc = 0;
243 if (h->temporal_id == 0 &&
244 h->nal_unit_type != NAL_TRAIL_N &&
245 h->nal_unit_type != NAL_TSA_N &&
246 h->nal_unit_type != NAL_STSA_N &&
247 h->nal_unit_type != NAL_RADL_N &&
248 h->nal_unit_type != NAL_RASL_N &&
249 h->nal_unit_type != NAL_RADL_R &&
250 h->nal_unit_type != NAL_RASL_R)
253 return 0; /* no need to evaluate the rest */
257 /* didn't find a picture! */
258 av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
262 static int hevc_parse(AVCodecParserContext *s,
263 AVCodecContext *avctx,
264 const uint8_t **poutbuf, int *poutbuf_size,
265 const uint8_t *buf, int buf_size)
268 ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
270 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
273 next = hevc_find_frame_end(s, buf, buf_size);
274 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
281 parse_nal_units(s, avctx, buf, buf_size);
284 *poutbuf_size = buf_size;
288 // Split after the parameter sets at the beginning of the stream if they exist.
289 static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
291 const uint8_t *ptr = buf, *end = buf + buf_size;
296 ptr = avpriv_find_start_code(ptr, end, &state);
297 if ((state >> 8) != START_CODE)
299 nut = (state >> 1) & 0x3F;
300 if (nut >= NAL_VPS && nut <= NAL_PPS)
303 return ptr - 4 - buf;
304 else // no parameter set at the beginning of the stream
310 static int hevc_init(AVCodecParserContext *s)
312 HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
313 h->HEVClc = av_mallocz(sizeof(HEVCLocalContext));
315 return AVERROR(ENOMEM);
316 h->skipped_bytes_pos_size = INT_MAX;
321 static void hevc_close(AVCodecParserContext *s)
324 HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
325 ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
326 HEVCParamSets *ps = &h->ps;
327 HEVCPacket *pkt = &h->pkt;
329 av_freep(&h->skipped_bytes_pos);
330 av_freep(&h->HEVClc);
331 av_freep(&pc->buffer);
333 for (i = 0; i < FF_ARRAY_ELEMS(ps->vps_list); i++)
334 av_buffer_unref(&ps->vps_list[i]);
335 for (i = 0; i < FF_ARRAY_ELEMS(ps->sps_list); i++)
336 av_buffer_unref(&ps->sps_list[i]);
337 for (i = 0; i < FF_ARRAY_ELEMS(ps->pps_list); i++)
338 av_buffer_unref(&ps->pps_list[i]);
342 for (i = 0; i < pkt->nals_allocated; i++)
343 av_freep(&pkt->nals[i].rbsp_buffer);
344 av_freep(&pkt->nals);
345 pkt->nals_allocated = 0;
348 AVCodecParser ff_hevc_parser = {
349 .codec_ids = { AV_CODEC_ID_HEVC },
350 .priv_data_size = sizeof(HEVCParseContext),
351 .parser_init = hevc_init,
352 .parser_parse = hevc_parse,
353 .parser_close = hevc_close,