yohhoy

#!/usr/bin/env python3
import sys
import struct

if len(sys.argv) < 2:
  print("Usage: aac_parer.py <target.aac>")
  exit()

aacfile = open(sys.argv[1], 'rb')
frame_no = 1

yohhoy

/*
 * Convert from OpenCV image and write movie with FFmpeg
 *
 * Copyright (c) 2016 yohhoy
 */
#include <iostream>
#include <vector>
// FFmpeg
extern "C" {
#include <libavformat/avformat.h>

yohhoy

https://www.ffmpeg.org/doxygen/trunk/dump_8c_source.html#l00454

• fps = st->avg_frame_rate
• tbr = st->r_frame_rate
• tbn = st->time_base
• tbc = st->codec->time_base

AVStream::avg_frame_rate

Average framerate.

• demuxing: May be set by libavformat when creating the stream or in avformat_find_stream_info().
• muxing: May be set by the caller before avformat_write_header().

yohhoy

/*
 * C11 <threads.h> emulation library
 *
 * (C) Copyright yohhoy 2012.
 * Distributed under the Boost Software License, Version 1.0.
 * (See copy at http://www.boost.org/LICENSE_1_0.txt)
 */
#ifndef EMULATED_THREADS_H_INCLUDED_
#define EMULATED_THREADS_H_INCLUDED_

yohhoy

/*
 * Read video frame with FFmpeg and convert to OpenCV image
 *
 * Copyright (c) 2016 yohhoy
 */
#include <iostream>
#include <vector>
// FFmpeg
extern "C" {
#include <libavformat/avformat.h>

yohhoy

bool starts_with_utf8bom(std::string_view s)
{
  constexpr char utf8_bom[3] = { 0xEF, 0xBB, 0xBF };
  return s.length() >= 3 && std::equal(utf8_bom, utf8_bom + 3, s.begin());
}

std::string& erase_utf8bom(std::string& text)
{
  if (starts_with_utf8bom(text)) {
    text.erase(0, 3);

yohhoy

#include <chrono>
#include <condition_variable>
#include <mutex>
#include <utility>
#include <vector>


struct closed_queue : std::exception {};

template <typename T, typename Clock = std::chrono::system_clock>

yohhoy

AAC

ISO/IEC 14496-3, 1.6.2.1 AudioSpecificConfig

AudioSpecificConfig() {
	audioObjectType = GetAudioObjectType();
	samplingFrequencyIndex; // 4 bslbf
	if (samplingFrequencyIndex == 0xf) {
		samplingFrequency; // 24 uimsbf
	}

yohhoy

#include <type_traits>

int main() {
  int x = 42;
  static_assert(std::is_same_v<decltype( x ), int>);
  static_assert(std::is_same_v<decltype((x)), int&>);

  int (y) = 42;  // redundant parentheses
  static_assert(std::is_same_v<decltype( y ), int>);
  static_assert(std::is_same_v<decltype((y)), int&>);

yohhoy

Y  = a * R + b * G + c * B
Cb = (B - Y) / d
Cr = (R - Y) / e

	BT.601	BT.709	BT.2020
a	0.299	0.2126	0.2627
b	0.587	0.7152	0.6780