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![Michael Niedermayer](/assets/img/avatar_default.png)
* commit '218d6844b37d339ffbf2044ad07d8be7767e2734': h264dsp: Factorize code into a new function, h264_find_start_code_candidate Conflicts: libavcodec/h264_parser.c Merged-by: Michael Niedermayer <michaelni@gmx.at>
460 lines
15 KiB
C
460 lines
15 KiB
C
/*
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* H.26L/H.264/AVC/JVT/14496-10/... parser
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* H.264 / AVC / MPEG4 part10 parser.
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* @author Michael Niedermayer <michaelni@gmx.at>
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*/
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#define UNCHECKED_BITSTREAM_READER 1
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#include "libavutil/attributes.h"
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#include "parser.h"
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#include "h264data.h"
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#include "golomb.h"
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#include "internal.h"
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static int h264_find_frame_end(H264Context *h, const uint8_t *buf,
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int buf_size)
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{
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int i, j;
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uint32_t state;
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ParseContext *pc = &h->parse_context;
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int next_avc= h->is_avc ? 0 : buf_size;
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// mb_addr= pc->mb_addr - 1;
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state = pc->state;
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if (state > 13)
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state = 7;
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if (h->is_avc && !h->nal_length_size)
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av_log(h->avctx, AV_LOG_ERROR, "AVC-parser: nal length size invalid\n");
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for (i = 0; i < buf_size; i++) {
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if (i >= next_avc) {
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int nalsize = 0;
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i = next_avc;
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for (j = 0; j < h->nal_length_size; j++)
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nalsize = (nalsize << 8) | buf[i++];
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if (nalsize <= 0 || nalsize > buf_size - i) {
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av_log(h->avctx, AV_LOG_ERROR, "AVC-parser: nal size %d remaining %d\n", nalsize, buf_size - i);
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return buf_size;
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}
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next_avc = i + nalsize;
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state = 5;
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}
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if (state == 7) {
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i += h->h264dsp.h264_find_start_code_candidate(buf + i, next_avc - i);
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if (i < next_avc)
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state = 2;
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} else if (state <= 2) {
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if (buf[i] == 1)
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state ^= 5; // 2->7, 1->4, 0->5
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else if (buf[i])
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state = 7;
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else
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state >>= 1; // 2->1, 1->0, 0->0
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} else if (state <= 5) {
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int v = buf[i] & 0x1F;
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if (v == 6 || v == 7 || v == 8 || v == 9) {
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if (pc->frame_start_found) {
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i++;
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goto found;
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}
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} else if (v == 1 || v == 2 || v == 5) {
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state += 8;
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continue;
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}
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state = 7;
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} else {
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h->parse_history[h->parse_history_count++]= buf[i];
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if (h->parse_history_count>3) {
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unsigned int mb, last_mb= h->parse_last_mb;
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GetBitContext gb;
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init_get_bits(&gb, h->parse_history, 8*h->parse_history_count);
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h->parse_history_count=0;
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mb= get_ue_golomb_long(&gb);
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last_mb= h->parse_last_mb;
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h->parse_last_mb= mb;
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if (pc->frame_start_found) {
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if (mb <= last_mb)
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goto found;
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} else
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pc->frame_start_found = 1;
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state = 7;
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}
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}
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}
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pc->state = state;
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if (h->is_avc)
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return next_avc;
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return END_NOT_FOUND;
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found:
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pc->state = 7;
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pc->frame_start_found = 0;
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if (h->is_avc)
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return next_avc;
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return i - (state & 5) - 3 * (state > 7);
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}
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/**
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* Parse NAL units of found picture and decode some basic information.
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*
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* @param s parser context.
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* @param avctx codec context.
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* @param buf buffer with field/frame data.
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* @param buf_size size of the buffer.
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*/
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static inline int parse_nal_units(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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H264Context *h = s->priv_data;
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const uint8_t *buf_end = buf + buf_size;
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unsigned int pps_id;
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unsigned int slice_type;
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int state = -1;
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const uint8_t *ptr;
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int q264 = buf_size >=4 && !memcmp("Q264", buf, 4);
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int field_poc[2];
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/* set some sane default values */
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s->pict_type = AV_PICTURE_TYPE_I;
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s->key_frame = 0;
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s->picture_structure = AV_PICTURE_STRUCTURE_UNKNOWN;
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h->avctx = avctx;
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h->sei_recovery_frame_cnt = -1;
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h->sei_dpb_output_delay = 0;
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h->sei_cpb_removal_delay = -1;
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h->sei_buffering_period_present = 0;
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h->sei_fpa.frame_packing_arrangement_cancel_flag = -1;
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if (!buf_size)
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return 0;
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for (;;) {
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int src_length, dst_length, consumed, nalsize = 0;
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if (h->is_avc) {
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int i;
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if (h->nal_length_size >= buf_end - buf) break;
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nalsize = 0;
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for (i = 0; i < h->nal_length_size; i++)
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nalsize = (nalsize << 8) | *buf++;
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if (nalsize <= 0 || nalsize > buf_end - buf) {
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av_log(h->avctx, AV_LOG_ERROR, "AVC: nal size %d\n", nalsize);
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break;
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}
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src_length = nalsize;
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} else {
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buf = avpriv_find_start_code(buf, buf_end, &state);
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if (buf >= buf_end)
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break;
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--buf;
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src_length = buf_end - buf;
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}
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switch (state & 0x1f) {
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case NAL_SLICE:
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case NAL_IDR_SLICE:
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// Do not walk the whole buffer just to decode slice header
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if (src_length > 20)
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src_length = 20;
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break;
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}
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ptr = ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
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if (ptr == NULL || dst_length < 0)
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break;
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init_get_bits(&h->gb, ptr, 8 * dst_length);
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switch (h->nal_unit_type) {
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case NAL_SPS:
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ff_h264_decode_seq_parameter_set(h);
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break;
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case NAL_PPS:
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ff_h264_decode_picture_parameter_set(h, h->gb.size_in_bits);
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break;
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case NAL_SEI:
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ff_h264_decode_sei(h);
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break;
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case NAL_IDR_SLICE:
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s->key_frame = 1;
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h->prev_frame_num = 0;
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h->prev_frame_num_offset = 0;
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h->prev_poc_msb =
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h->prev_poc_lsb = 0;
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/* fall through */
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case NAL_SLICE:
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get_ue_golomb_long(&h->gb); // skip first_mb_in_slice
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slice_type = get_ue_golomb_31(&h->gb);
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s->pict_type = golomb_to_pict_type[slice_type % 5];
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if (h->sei_recovery_frame_cnt >= 0) {
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/* key frame, since recovery_frame_cnt is set */
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s->key_frame = 1;
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}
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pps_id = get_ue_golomb(&h->gb);
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if (pps_id >= MAX_PPS_COUNT) {
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av_log(h->avctx, AV_LOG_ERROR,
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"pps_id out of range\n");
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return -1;
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}
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if (!h->pps_buffers[pps_id]) {
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av_log(h->avctx, AV_LOG_ERROR,
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"non-existing PPS referenced\n");
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return -1;
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}
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h->pps = *h->pps_buffers[pps_id];
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if (!h->sps_buffers[h->pps.sps_id]) {
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av_log(h->avctx, AV_LOG_ERROR,
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"non-existing SPS referenced\n");
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return -1;
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}
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h->sps = *h->sps_buffers[h->pps.sps_id];
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h->frame_num = get_bits(&h->gb, h->sps.log2_max_frame_num);
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avctx->profile = ff_h264_get_profile(&h->sps);
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avctx->level = h->sps.level_idc;
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if (h->sps.frame_mbs_only_flag) {
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h->picture_structure = PICT_FRAME;
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} else {
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if (get_bits1(&h->gb)) { // field_pic_flag
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h->picture_structure = PICT_TOP_FIELD + get_bits1(&h->gb); // bottom_field_flag
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} else {
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h->picture_structure = PICT_FRAME;
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}
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}
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if (h->nal_unit_type == NAL_IDR_SLICE)
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get_ue_golomb(&h->gb); /* idr_pic_id */
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if (h->sps.poc_type == 0) {
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h->poc_lsb = get_bits(&h->gb, h->sps.log2_max_poc_lsb);
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if (h->pps.pic_order_present == 1 &&
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h->picture_structure == PICT_FRAME)
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h->delta_poc_bottom = get_se_golomb(&h->gb);
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}
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if (h->sps.poc_type == 1 &&
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!h->sps.delta_pic_order_always_zero_flag) {
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h->delta_poc[0] = get_se_golomb(&h->gb);
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if (h->pps.pic_order_present == 1 &&
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h->picture_structure == PICT_FRAME)
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h->delta_poc[1] = get_se_golomb(&h->gb);
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}
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ff_init_poc(h, field_poc, &s->output_picture_number);
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if (h->sps.pic_struct_present_flag) {
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switch (h->sei_pic_struct) {
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case SEI_PIC_STRUCT_TOP_FIELD:
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case SEI_PIC_STRUCT_BOTTOM_FIELD:
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s->repeat_pict = 0;
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break;
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case SEI_PIC_STRUCT_FRAME:
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case SEI_PIC_STRUCT_TOP_BOTTOM:
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case SEI_PIC_STRUCT_BOTTOM_TOP:
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s->repeat_pict = 1;
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break;
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case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
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case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
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s->repeat_pict = 2;
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break;
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case SEI_PIC_STRUCT_FRAME_DOUBLING:
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s->repeat_pict = 3;
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break;
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case SEI_PIC_STRUCT_FRAME_TRIPLING:
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s->repeat_pict = 5;
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break;
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default:
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s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
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break;
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}
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} else {
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s->repeat_pict = h->picture_structure == PICT_FRAME ? 1 : 0;
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}
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if (h->picture_structure == PICT_FRAME) {
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s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
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if (h->sps.pic_struct_present_flag) {
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switch (h->sei_pic_struct) {
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case SEI_PIC_STRUCT_TOP_BOTTOM:
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case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
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s->field_order = AV_FIELD_TT;
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break;
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case SEI_PIC_STRUCT_BOTTOM_TOP:
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case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
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s->field_order = AV_FIELD_BB;
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break;
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default:
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s->field_order = AV_FIELD_PROGRESSIVE;
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break;
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}
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} else {
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if (field_poc[0] < field_poc[1])
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s->field_order = AV_FIELD_TT;
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else if (field_poc[0] > field_poc[1])
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s->field_order = AV_FIELD_BB;
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else
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s->field_order = AV_FIELD_PROGRESSIVE;
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}
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} else {
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if (h->picture_structure == PICT_TOP_FIELD)
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s->picture_structure = AV_PICTURE_STRUCTURE_TOP_FIELD;
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else
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s->picture_structure = AV_PICTURE_STRUCTURE_BOTTOM_FIELD;
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s->field_order = AV_FIELD_UNKNOWN;
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}
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return 0; /* no need to evaluate the rest */
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}
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buf += h->is_avc ? nalsize : consumed;
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}
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if (q264)
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return 0;
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/* didn't find a picture! */
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av_log(h->avctx, AV_LOG_ERROR, "missing picture in access unit with size %d\n", buf_size);
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return -1;
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}
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static int h264_parse(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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H264Context *h = s->priv_data;
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ParseContext *pc = &h->parse_context;
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int next;
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if (!h->got_first) {
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h->got_first = 1;
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if (avctx->extradata_size) {
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h->avctx = avctx;
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// must be done like in decoder, otherwise opening the parser,
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// letting it create extradata and then closing and opening again
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// will cause has_b_frames to be always set.
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// Note that estimate_timings_from_pts does exactly this.
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if (!avctx->has_b_frames)
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h->low_delay = 1;
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ff_h264_decode_extradata(h, avctx->extradata, avctx->extradata_size);
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}
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}
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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next = h264_find_frame_end(h, buf, buf_size);
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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if (next < 0 && next != END_NOT_FOUND) {
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av_assert1(pc->last_index + next >= 0);
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h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); // update state
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}
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}
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parse_nal_units(s, avctx, buf, buf_size);
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if (h->sei_cpb_removal_delay >= 0) {
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s->dts_sync_point = h->sei_buffering_period_present;
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s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
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s->pts_dts_delta = h->sei_dpb_output_delay;
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} else {
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s->dts_sync_point = INT_MIN;
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s->dts_ref_dts_delta = INT_MIN;
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s->pts_dts_delta = INT_MIN;
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}
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if (s->flags & PARSER_FLAG_ONCE) {
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s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
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}
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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static int h264_split(AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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int i;
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uint32_t state = -1;
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int has_sps = 0;
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for (i = 0; i <= buf_size; i++) {
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if ((state & 0xFFFFFF1F) == 0x107)
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has_sps = 1;
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/* if ((state&0xFFFFFF1F) == 0x101 ||
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* (state&0xFFFFFF1F) == 0x102 ||
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* (state&0xFFFFFF1F) == 0x105) {
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* }
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*/
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if ((state & 0xFFFFFF00) == 0x100 && (state & 0xFFFFFF1F) != 0x107 &&
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(state & 0xFFFFFF1F) != 0x108 && (state & 0xFFFFFF1F) != 0x109) {
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if (has_sps) {
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while (i > 4 && buf[i - 5] == 0)
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i--;
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return i - 4;
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}
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}
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if (i < buf_size)
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state = (state << 8) | buf[i];
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}
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return 0;
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}
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static void close(AVCodecParserContext *s)
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{
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H264Context *h = s->priv_data;
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ParseContext *pc = &h->parse_context;
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av_free(pc->buffer);
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ff_h264_free_context(h);
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}
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static av_cold int init(AVCodecParserContext *s)
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{
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H264Context *h = s->priv_data;
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h->thread_context[0] = h;
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h->slice_context_count = 1;
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ff_h264dsp_init(&h->h264dsp, 8, 1);
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return 0;
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}
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AVCodecParser ff_h264_parser = {
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.codec_ids = { AV_CODEC_ID_H264 },
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.priv_data_size = sizeof(H264Context),
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.parser_init = init,
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.parser_parse = h264_parse,
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.parser_close = close,
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.split = h264_split,
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};
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