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 const uint8_t *buf_end = buf + buf_size;
98 /* set some sane default values */
99 s->pict_type = AV_PICTURE_TYPE_I;
101 s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
108 if (h->nals_allocated < 1) {
109 HEVCNAL *tmp = av_realloc_array(h->nals, 1, sizeof(*tmp));
111 return AVERROR(ENOMEM);
113 memset(h->nals, 0, sizeof(*tmp));
114 h->nals_allocated = 1;
120 int src_length, consumed;
121 buf = avpriv_find_start_code(buf, buf_end, &state);
122 if (--buf + 2 >= buf_end)
124 src_length = buf_end - buf;
126 h->nal_unit_type = (*buf >> 1) & 0x3f;
127 h->temporal_id = (*(buf + 1) & 0x07) - 1;
128 if (h->nal_unit_type <= NAL_CRA_NUT) {
129 // Do not walk the whole buffer just to decode slice segment header
134 consumed = ff_hevc_extract_rbsp(h, buf, src_length, nal);
138 init_get_bits8(gb, nal->data + 2, nal->size);
139 switch (h->nal_unit_type) {
141 ff_hevc_decode_nal_vps(gb, avctx, ps);
144 ff_hevc_decode_nal_sps(gb, avctx, ps, h->apply_defdispwin);
147 ff_hevc_decode_nal_pps(gb, avctx, ps);
151 ff_hevc_decode_nal_sei(h);
169 sh->first_slice_in_pic_flag = get_bits1(gb);
170 s->picture_structure = h->picture_struct;
171 s->field_order = h->picture_struct;
175 sh->no_output_of_prior_pics_flag = get_bits1(gb);
178 sh->pps_id = get_ue_golomb(gb);
179 if (sh->pps_id >= MAX_PPS_COUNT || !ps->pps_list[sh->pps_id]) {
180 av_log(h->avctx, AV_LOG_ERROR, "PPS id out of range: %d\n", sh->pps_id);
181 return AVERROR_INVALIDDATA;
183 ps->pps = (HEVCPPS*)ps->pps_list[sh->pps_id]->data;
185 if (ps->pps->sps_id >= MAX_SPS_COUNT || !ps->sps_list[ps->pps->sps_id]) {
186 av_log(h->avctx, AV_LOG_ERROR, "SPS id out of range: %d\n", ps->pps->sps_id);
187 return AVERROR_INVALIDDATA;
189 if (ps->sps != (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data) {
190 ps->sps = (HEVCSPS*)ps->sps_list[ps->pps->sps_id]->data;
191 ps->vps = (HEVCVPS*)ps->vps_list[ps->sps->vps_id]->data;
194 if (!sh->first_slice_in_pic_flag) {
195 int slice_address_length;
197 if (ps->pps->dependent_slice_segments_enabled_flag)
198 sh->dependent_slice_segment_flag = get_bits1(gb);
200 sh->dependent_slice_segment_flag = 0;
202 slice_address_length = av_ceil_log2_c(ps->sps->ctb_width *
203 ps->sps->ctb_height);
204 sh->slice_segment_addr = slice_address_length ? get_bits(gb, slice_address_length) : 0;
205 if (sh->slice_segment_addr >= ps->sps->ctb_width * ps->sps->ctb_height) {
206 av_log(h->avctx, AV_LOG_ERROR, "Invalid slice segment address: %u.\n",
207 sh->slice_segment_addr);
208 return AVERROR_INVALIDDATA;
211 sh->dependent_slice_segment_flag = 0;
213 if (sh->dependent_slice_segment_flag)
216 for (i = 0; i < ps->pps->num_extra_slice_header_bits; i++)
217 skip_bits(gb, 1); // slice_reserved_undetermined_flag[]
219 sh->slice_type = get_ue_golomb(gb);
220 if (!(sh->slice_type == I_SLICE || sh->slice_type == P_SLICE ||
221 sh->slice_type == B_SLICE)) {
222 av_log(h->avctx, AV_LOG_ERROR, "Unknown slice type: %d.\n",
224 return AVERROR_INVALIDDATA;
226 s->pict_type = sh->slice_type == B_SLICE ? AV_PICTURE_TYPE_B :
227 sh->slice_type == P_SLICE ? AV_PICTURE_TYPE_P :
230 if (ps->pps->output_flag_present_flag)
231 sh->pic_output_flag = get_bits1(gb);
233 if (ps->sps->separate_colour_plane_flag)
234 sh->colour_plane_id = get_bits(gb, 2);
237 sh->pic_order_cnt_lsb = get_bits(gb, ps->sps->log2_max_poc_lsb);
238 s->output_picture_number = h->poc = ff_hevc_compute_poc(h, sh->pic_order_cnt_lsb);
240 s->output_picture_number = h->poc = 0;
242 if (h->temporal_id == 0 &&
243 h->nal_unit_type != NAL_TRAIL_N &&
244 h->nal_unit_type != NAL_TSA_N &&
245 h->nal_unit_type != NAL_STSA_N &&
246 h->nal_unit_type != NAL_RADL_N &&
247 h->nal_unit_type != NAL_RASL_N &&
248 h->nal_unit_type != NAL_RADL_R &&
249 h->nal_unit_type != NAL_RASL_R)
252 return 0; /* no need to evaluate the rest */
256 /* didn't find a picture! */
257 av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit\n");
261 static int hevc_parse(AVCodecParserContext *s,
262 AVCodecContext *avctx,
263 const uint8_t **poutbuf, int *poutbuf_size,
264 const uint8_t *buf, int buf_size)
267 ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
269 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
272 next = hevc_find_frame_end(s, buf, buf_size);
273 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
280 parse_nal_units(s, avctx, buf, buf_size);
283 *poutbuf_size = buf_size;
287 // Split after the parameter sets at the beginning of the stream if they exist.
288 static int hevc_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
290 const uint8_t *ptr = buf, *end = buf + buf_size;
295 ptr = avpriv_find_start_code(ptr, end, &state);
296 if ((state >> 8) != START_CODE)
298 nut = (state >> 1) & 0x3F;
299 if (nut >= NAL_VPS && nut <= NAL_PPS)
302 return ptr - 4 - buf;
303 else // no parameter set at the beginning of the stream
309 static int hevc_init(AVCodecParserContext *s)
311 HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
312 h->HEVClc = av_mallocz(sizeof(HEVCLocalContext));
314 return AVERROR(ENOMEM);
315 h->skipped_bytes_pos_size = INT_MAX;
320 static void hevc_close(AVCodecParserContext *s)
323 HEVCContext *h = &((HEVCParseContext *)s->priv_data)->h;
324 ParseContext *pc = &((HEVCParseContext *)s->priv_data)->pc;
325 HEVCParamSets *ps = &h->ps;
327 av_freep(&h->skipped_bytes_pos);
328 av_freep(&h->HEVClc);
329 av_freep(&pc->buffer);
331 for (i = 0; i < FF_ARRAY_ELEMS(ps->vps_list); i++)
332 av_buffer_unref(&ps->vps_list[i]);
333 for (i = 0; i < FF_ARRAY_ELEMS(ps->sps_list); i++)
334 av_buffer_unref(&ps->sps_list[i]);
335 for (i = 0; i < FF_ARRAY_ELEMS(ps->pps_list); i++)
336 av_buffer_unref(&ps->pps_list[i]);
340 for (i = 0; i < h->nals_allocated; i++)
341 av_freep(&h->nals[i].rbsp_buffer);
343 h->nals_allocated = 0;
346 AVCodecParser ff_hevc_parser = {
347 .codec_ids = { AV_CODEC_ID_HEVC },
348 .priv_data_size = sizeof(HEVCParseContext),
349 .parser_init = hevc_init,
350 .parser_parse = hevc_parse,
351 .parser_close = hevc_close,