mirror of https://github.com/FFmpeg/FFmpeg.git
Signed-off-by: James Almer <jamrial@gmail.com>release/7.1
James Almer
8 months ago
parent
0eacad6921
commit
53c8d417ed
15 changed files with 288 additions and 218 deletions
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/*
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* NAL helper functions for muxers |
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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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#include <stdint.h> |
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#include <string.h> |
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#include "libavutil/mem.h" |
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#include "libavutil/error.h" |
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#include "libavcodec/defs.h" |
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#include "avio.h" |
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#include "avio_internal.h" |
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#include "nal.h" |
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static const uint8_t *nal_find_startcode_internal(const uint8_t *p, const uint8_t *end) |
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{ |
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const uint8_t *a = p + 4 - ((intptr_t)p & 3); |
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for (end -= 3; p < a && p < end; p++) { |
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if (p[0] == 0 && p[1] == 0 && p[2] == 1) |
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return p; |
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} |
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for (end -= 3; p < end; p += 4) { |
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uint32_t x = *(const uint32_t*)p; |
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// if ((x - 0x01000100) & (~x) & 0x80008000) // little endian
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// if ((x - 0x00010001) & (~x) & 0x00800080) // big endian
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if ((x - 0x01010101) & (~x) & 0x80808080) { // generic
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if (p[1] == 0) { |
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if (p[0] == 0 && p[2] == 1) |
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return p; |
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if (p[2] == 0 && p[3] == 1) |
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return p+1; |
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} |
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if (p[3] == 0) { |
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if (p[2] == 0 && p[4] == 1) |
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return p+2; |
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if (p[4] == 0 && p[5] == 1) |
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return p+3; |
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} |
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} |
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} |
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for (end += 3; p < end; p++) { |
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if (p[0] == 0 && p[1] == 0 && p[2] == 1) |
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return p; |
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} |
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return end + 3; |
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} |
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const uint8_t *ff_nal_find_startcode(const uint8_t *p, const uint8_t *end){ |
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const uint8_t *out = nal_find_startcode_internal(p, end); |
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if(p<out && out<end && !out[-1]) out--; |
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return out; |
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} |
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static int nal_parse_units(AVIOContext *pb, NALUList *list, |
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const uint8_t *buf_in, int size) |
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{ |
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const uint8_t *p = buf_in; |
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const uint8_t *end = p + size; |
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const uint8_t *nal_start, *nal_end; |
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size = 0; |
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nal_start = ff_nal_find_startcode(p, end); |
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for (;;) { |
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const size_t nalu_limit = SIZE_MAX / sizeof(*list->nalus); |
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while (nal_start < end && !*(nal_start++)); |
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if (nal_start == end) |
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break; |
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nal_end = ff_nal_find_startcode(nal_start, end); |
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if (pb) { |
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avio_wb32(pb, nal_end - nal_start); |
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avio_write(pb, nal_start, nal_end - nal_start); |
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} else if (list->nb_nalus >= nalu_limit) { |
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return AVERROR(ERANGE); |
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} else { |
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NALU *tmp = av_fast_realloc(list->nalus, &list->nalus_array_size, |
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(list->nb_nalus + 1) * sizeof(*list->nalus)); |
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if (!tmp) |
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return AVERROR(ENOMEM); |
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list->nalus = tmp; |
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tmp[list->nb_nalus++] = (NALU){ .offset = nal_start - p, |
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.size = nal_end - nal_start }; |
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} |
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size += 4 + nal_end - nal_start; |
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nal_start = nal_end; |
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} |
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return size; |
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} |
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int ff_nal_parse_units(AVIOContext *pb, const uint8_t *buf_in, int size) |
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{ |
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return nal_parse_units(pb, NULL, buf_in, size); |
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} |
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int ff_nal_units_create_list(NALUList *list, const uint8_t *buf, int size) |
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{ |
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list->nb_nalus = 0; |
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return nal_parse_units(NULL, list, buf, size); |
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} |
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void ff_nal_units_write_list(const NALUList *list, AVIOContext *pb, |
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const uint8_t *buf) |
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{ |
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for (unsigned i = 0; i < list->nb_nalus; i++) { |
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avio_wb32(pb, list->nalus[i].size); |
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avio_write(pb, buf + list->nalus[i].offset, list->nalus[i].size); |
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} |
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} |
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int ff_nal_parse_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size) |
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{ |
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AVIOContext *pb; |
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int ret = avio_open_dyn_buf(&pb); |
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if(ret < 0) |
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return ret; |
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ff_nal_parse_units(pb, buf_in, *size); |
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*size = avio_close_dyn_buf(pb, buf); |
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return 0; |
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} |
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const uint8_t *ff_nal_mp4_find_startcode(const uint8_t *start, |
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const uint8_t *end, |
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int nal_length_size) |
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{ |
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unsigned int res = 0; |
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if (end - start < nal_length_size) |
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return NULL; |
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while (nal_length_size--) |
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res = (res << 8) | *start++; |
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if (res > end - start) |
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return NULL; |
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return start + res; |
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} |
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uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len, |
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uint32_t *dst_len, int header_len) |
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{ |
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uint8_t *dst; |
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uint32_t i, len; |
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dst = av_malloc(src_len + AV_INPUT_BUFFER_PADDING_SIZE); |
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if (!dst) |
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return NULL; |
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/* NAL unit header */ |
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i = len = 0; |
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while (i < header_len && i < src_len) |
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dst[len++] = src[i++]; |
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while (i + 2 < src_len) |
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if (!src[i] && !src[i + 1] && src[i + 2] == 3) { |
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dst[len++] = src[i++]; |
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dst[len++] = src[i++]; |
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i++; // remove emulation_prevention_three_byte
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} else |
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dst[len++] = src[i++]; |
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while (i < src_len) |
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dst[len++] = src[i++]; |
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memset(dst + len, 0, AV_INPUT_BUFFER_PADDING_SIZE); |
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*dst_len = len; |
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return dst; |
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} |
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@ -0,0 +1,67 @@ |
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/*
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* NAL helper functions for muxers |
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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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#ifndef AVFORMAT_NAL_H |
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#define AVFORMAT_NAL_H |
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#include <stdint.h> |
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#include "avio.h" |
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typedef struct NALU { |
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int offset; |
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uint32_t size; |
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} NALU; |
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typedef struct NALUList { |
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NALU *nalus; |
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unsigned nalus_array_size; |
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unsigned nb_nalus; ///< valid entries in nalus
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} NALUList; |
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/* This function will parse the given annex B buffer and create
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* a NALUList from it. This list can be passed to ff_nal_units_write_list() |
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* to write the access unit reformatted to mp4. |
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* |
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* @param list A NALUList. The list->nalus and list->nalus_array_size |
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* must be valid when calling this function and may be updated. |
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* nb_nalus is set by this function on success. |
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* @param buf buffer containing annex B H.264 or H.265. Must be padded. |
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* @param size size of buf, excluding padding. |
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* @return < 0 on error, the size of the mp4-style packet on success. |
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*/ |
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int ff_nal_units_create_list(NALUList *list, const uint8_t *buf, int size); |
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/* Writes a NALUList to the specified AVIOContext. The list must originate
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* from ff_nal_units_create_list() with the same buf. */ |
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void ff_nal_units_write_list(const NALUList *list, AVIOContext *pb, |
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const uint8_t *buf); |
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const uint8_t *ff_nal_find_startcode(const uint8_t *p, const uint8_t *end); |
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const uint8_t *ff_nal_mp4_find_startcode(const uint8_t *start, |
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const uint8_t *end, |
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int nal_length_size); |
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int ff_nal_parse_units(AVIOContext *s, const uint8_t *buf, int size); |
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int ff_nal_parse_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size); |
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uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len, |
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uint32_t *dst_len, int header_len); |
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#endif /* AVFORMAT_NAL_H */ |
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