2 * H.26L/H.264/AVC/JVT/14496-10/... parser
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
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.
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.
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
24 * H.264 / AVC / MPEG4 part10 parser.
25 * @author Michael Niedermayer <michaelni@gmx.at>
28 #define UNCHECKED_BITSTREAM_READER 1
30 #include "libavutil/attributes.h"
37 static int h264_find_frame_end(H264Context *h, const uint8_t *buf,
42 ParseContext *pc = &h->parse_context;
43 int next_avc= h->is_avc ? 0 : buf_size;
45 // mb_addr= pc->mb_addr - 1;
50 if (h->is_avc && !h->nal_length_size)
51 av_log(h->avctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
53 for (i = 0; i < buf_size; i++) {
57 for (j = 0; j < h->nal_length_size; j++)
58 nalsize = (nalsize << 8) | buf[i++];
59 if (nalsize <= 0 || nalsize > buf_size - i) {
60 av_log(h->avctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
63 next_avc = i + nalsize;
68 #if HAVE_FAST_UNALIGNED
69 /* we check i < buf_size instead of i + 3 / 7 because it is
70 * simpler and there must be FF_INPUT_BUFFER_PADDING_SIZE
74 while (i < next_avc &&
75 !((~*(const uint64_t *)(buf + i) &
76 (*(const uint64_t *)(buf + i) - 0x0101010101010101ULL)) &
77 0x8080808080808080ULL))
80 while (i < next_avc &&
81 !((~*(const uint32_t *)(buf + i) &
82 (*(const uint32_t *)(buf + i) - 0x01010101U)) &
87 for (; i < next_avc; i++)
92 } else if (state <= 2) {
94 state ^= 5; // 2->7, 1->4, 0->5
98 state >>= 1; // 2->1, 1->0, 0->0
99 } else if (state <= 5) {
100 int v = buf[i] & 0x1F;
101 if (v == 6 || v == 7 || v == 8 || v == 9) {
102 if (pc->frame_start_found) {
106 } else if (v == 1 || v == 2 || v == 5) {
112 h->parse_history[h->parse_history_count++]= buf[i];
113 if (h->parse_history_count>3) {
114 unsigned int mb, last_mb= h->parse_last_mb;
117 init_get_bits(&gb, h->parse_history, 8*h->parse_history_count);
118 h->parse_history_count=0;
119 mb= get_ue_golomb_long(&gb);
120 last_mb= h->parse_last_mb;
121 h->parse_last_mb= mb;
122 if (pc->frame_start_found) {
126 pc->frame_start_found = 1;
134 return END_NOT_FOUND;
138 pc->frame_start_found = 0;
141 return i - (state & 5) - 3 * (state > 7);
145 * Parse NAL units of found picture and decode some basic information.
147 * @param s parser context.
148 * @param avctx codec context.
149 * @param buf buffer with field/frame data.
150 * @param buf_size size of the buffer.
152 static inline int parse_nal_units(AVCodecParserContext *s,
153 AVCodecContext *avctx,
154 const uint8_t *buf, int buf_size)
156 H264Context *h = s->priv_data;
157 const uint8_t *buf_end = buf + buf_size;
159 unsigned int slice_type;
162 int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
165 /* set some sane default values */
166 s->pict_type = AV_PICTURE_TYPE_I;
168 s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
171 h->sei_recovery_frame_cnt = -1;
172 h->sei_dpb_output_delay = 0;
173 h->sei_cpb_removal_delay = -1;
174 h->sei_buffering_period_present = 0;
180 int src_length, dst_length, consumed, nalsize = 0;
183 if (h->nal_length_size >= buf_end - buf) break;
185 for (i = 0; i < h->nal_length_size; i++)
186 nalsize = (nalsize << 8) | *buf++;
187 if (nalsize <= 0 || nalsize > buf_end - buf) {
188 av_log(h->avctx, AV_LOG_ERROR, "AVC: nal size %d\n", nalsize);
191 src_length = nalsize;
193 buf = avpriv_find_start_code(buf, buf_end, &state);
197 src_length = buf_end - buf;
199 switch (state & 0x1f) {
202 // Do not walk the whole buffer just to decode slice header
207 ptr = ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
208 if (ptr == NULL || dst_length < 0)
211 init_get_bits(&h->gb, ptr, 8 * dst_length);
212 switch (h->nal_unit_type) {
214 ff_h264_decode_seq_parameter_set(h);
217 ff_h264_decode_picture_parameter_set(h, h->gb.size_in_bits);
220 ff_h264_decode_sei(h);
225 h->prev_frame_num = 0;
226 h->prev_frame_num_offset = 0;
231 get_ue_golomb_long(&h->gb); // skip first_mb_in_slice
232 slice_type = get_ue_golomb_31(&h->gb);
233 s->pict_type = golomb_to_pict_type[slice_type % 5];
234 if (h->sei_recovery_frame_cnt >= 0) {
235 /* key frame, since recovery_frame_cnt is set */
238 pps_id = get_ue_golomb(&h->gb);
239 if (pps_id >= MAX_PPS_COUNT) {
240 av_log(h->avctx, AV_LOG_ERROR,
241 "pps_id out of range\n");
244 if (!h->pps_buffers[pps_id]) {
245 av_log(h->avctx, AV_LOG_ERROR,
246 "non-existing PPS referenced\n");
249 h->pps = *h->pps_buffers[pps_id];
250 if (!h->sps_buffers[h->pps.sps_id]) {
251 av_log(h->avctx, AV_LOG_ERROR,
252 "non-existing SPS referenced\n");
255 h->sps = *h->sps_buffers[h->pps.sps_id];
256 h->frame_num = get_bits(&h->gb, h->sps.log2_max_frame_num);
258 avctx->profile = ff_h264_get_profile(&h->sps);
259 avctx->level = h->sps.level_idc;
261 if (h->sps.frame_mbs_only_flag) {
262 h->picture_structure = PICT_FRAME;
264 if (get_bits1(&h->gb)) { // field_pic_flag
265 h->picture_structure = PICT_TOP_FIELD + get_bits1(&h->gb); // bottom_field_flag
267 h->picture_structure = PICT_FRAME;
271 if (h->nal_unit_type == NAL_IDR_SLICE)
272 get_ue_golomb(&h->gb); /* idr_pic_id */
273 if (h->sps.poc_type == 0) {
274 h->poc_lsb = get_bits(&h->gb, h->sps.log2_max_poc_lsb);
276 if (h->pps.pic_order_present == 1 &&
277 h->picture_structure == PICT_FRAME)
278 h->delta_poc_bottom = get_se_golomb(&h->gb);
281 if (h->sps.poc_type == 1 &&
282 !h->sps.delta_pic_order_always_zero_flag) {
283 h->delta_poc[0] = get_se_golomb(&h->gb);
285 if (h->pps.pic_order_present == 1 &&
286 h->picture_structure == PICT_FRAME)
287 h->delta_poc[1] = get_se_golomb(&h->gb);
290 ff_init_poc(h, field_poc, NULL);
292 if (h->sps.pic_struct_present_flag) {
293 switch (h->sei_pic_struct) {
294 case SEI_PIC_STRUCT_TOP_FIELD:
295 case SEI_PIC_STRUCT_BOTTOM_FIELD:
298 case SEI_PIC_STRUCT_FRAME:
299 case SEI_PIC_STRUCT_TOP_BOTTOM:
300 case SEI_PIC_STRUCT_BOTTOM_TOP:
303 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
304 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
307 case SEI_PIC_STRUCT_FRAME_DOUBLING:
310 case SEI_PIC_STRUCT_FRAME_TRIPLING:
314 s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
318 s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
321 if (h->picture_structure == PICT_FRAME) {
322 s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
323 if (h->sps.pic_struct_present_flag) {
324 switch (h->sei_pic_struct) {
325 case SEI_PIC_STRUCT_TOP_BOTTOM:
326 case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
327 s->field_order = AV_FIELD_TT;
329 case SEI_PIC_STRUCT_BOTTOM_TOP:
330 case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
331 s->field_order = AV_FIELD_BB;
334 s->field_order = AV_FIELD_PROGRESSIVE;
338 if (field_poc[0] < field_poc[1])
339 s->field_order = AV_FIELD_TT;
340 else if (field_poc[0] > field_poc[1])
341 s->field_order = AV_FIELD_BB;
343 s->field_order = AV_FIELD_PROGRESSIVE;
346 if (h->picture_structure == PICT_TOP_FIELD)
347 s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
349 s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
350 s->field_order = AV_FIELD_UNKNOWN;
353 return 0; /* no need to evaluate the rest */
355 buf += h->is_avc ? nalsize : consumed;
359 /* didn't find a picture! */
360 av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
364 static int h264_parse(AVCodecParserContext *s,
365 AVCodecContext *avctx,
366 const uint8_t **poutbuf, int *poutbuf_size,
367 const uint8_t *buf, int buf_size)
369 H264Context *h = s->priv_data;
370 ParseContext *pc = &h->parse_context;
375 if (avctx->extradata_size) {
377 // must be done like in decoder, otherwise opening the parser,
378 // letting it create extradata and then closing and opening again
379 // will cause has_b_frames to be always set.
380 // Note that estimate_timings_from_pts does exactly this.
381 if (!avctx->has_b_frames)
383 ff_h264_decode_extradata(h, avctx->extradata, avctx->extradata_size);
387 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
390 next = h264_find_frame_end(h, buf, buf_size);
392 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
398 if (next < 0 && next != END_NOT_FOUND) {
399 av_assert1(pc->last_index + next >= 0);
400 h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); // update state
404 parse_nal_units(s, avctx, buf, buf_size);
406 if (h->sei_cpb_removal_delay >= 0) {
407 s->dts_sync_point = h->sei_buffering_period_present;
408 s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
409 s->pts_dts_delta = h->sei_dpb_output_delay;
411 s->dts_sync_point = INT_MIN;
412 s->dts_ref_dts_delta = INT_MIN;
413 s->pts_dts_delta = INT_MIN;
416 if (s->flags & PARSER_FLAG_ONCE) {
417 s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
421 *poutbuf_size = buf_size;
425 static int h264_split(AVCodecContext *avctx,
426 const uint8_t *buf, int buf_size)
432 for (i = 0; i <= buf_size; i++) {
433 if ((state & 0xFFFFFF1F) == 0x107)
435 /* if ((state&0xFFFFFF1F) == 0x101 ||
436 * (state&0xFFFFFF1F) == 0x102 ||
437 * (state&0xFFFFFF1F) == 0x105) {
440 if ((state & 0xFFFFFF00) == 0x100 && (state & 0xFFFFFF1F) != 0x107 &&
441 (state & 0xFFFFFF1F) != 0x108 && (state & 0xFFFFFF1F) != 0x109) {
443 while (i > 4 && buf[i - 5] == 0)
449 state = (state << 8) | buf[i];
454 static void close(AVCodecParserContext *s)
456 H264Context *h = s->priv_data;
457 ParseContext *pc = &h->parse_context;
460 ff_h264_free_context(h);
463 static av_cold int init(AVCodecParserContext *s)
465 H264Context *h = s->priv_data;
466 h->thread_context[0] = h;
467 h->slice_context_count = 1;
471 AVCodecParser ff_h264_parser = {
472 .codec_ids = { AV_CODEC_ID_H264 },
473 .priv_data_size = sizeof(H264Context),
475 .parser_parse = h264_parse,
476 .parser_close = close,