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Improve reading MPEG audio info 

* Skip empty frames
* Improve error messages
This commit is contained in:
Martchus 2020-11-14 22:58:40 +01:00
parent 32e3cd9593
commit 9569065fb4
2 changed files with 25 additions and 7 deletions
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14
mpegaudio/mpegaudioframe.cpp
View File

@ -2,6 +2,8 @@
#include "../exceptions.h"
#include <c++utilities/conversion/stringbuilder.h>
#include <c++utilities/conversion/stringconversion.h>
#include <c++utilities/io/binaryreader.h>
using namespace std;
@ -46,15 +48,23 @@ const std::uint16_t MpegAudioFrame::s_bitrateTable[0x2][0x3][0xF] = { { { 0, 32,
*/
void MpegAudioFrame::parseHeader(BinaryReader &reader, Diagnostics &diag)
{
// read MPEG audio frame header
m_header = reader.readUInt32BE();
if (!isValid()) {
diag.emplace_back(DiagLevel::Critical, "Header is invalid.", "parsing MPEG audio frame header");
diag.emplace_back(DiagLevel::Critical,
"Frame 0x" % numberToString(m_header, 16) % " at 0x" % numberToString<std::int64_t>(reader.stream()->tellg() - 4l, 16) + " is invalid.",
"parsing MPEG audio frame header");
throw InvalidDataException();
}
// read XING header (see https://www.codeproject.com/Articles/8295/MPEG-Audio-Frame-Header#XINGHeader)
if (size() < s_xingHeaderOffset - 4 + 8) {
return;
}
reader.stream()->seekg(s_xingHeaderOffset - 4, ios_base::cur);
m_xingHeader = reader.readUInt64BE();
m_xingHeaderFlags = static_cast<XingHeaderFlags>(m_xingHeader & 0xffffffffuL);
if (isXingHeaderAvailable()) {
m_xingHeaderFlags = static_cast<XingHeaderFlags>(m_xingHeader & 0xffffffffuL);
if (isXingFramefieldPresent()) {
m_xingFramefield = reader.readUInt32BE();
}

18
mpegaudio/mpegaudioframestream.cpp
View File

@ -41,16 +41,24 @@ void MpegAudioFrameStream::internalParseHeader(Diagnostics &diag)
m_size = static_cast<std::uint64_t>(m_istream->tellg()) + 125u - m_startOffset;
}
m_istream->seekg(static_cast<streamoff>(m_startOffset), ios_base::beg);
// parse frame header
m_frames.emplace_back();
MpegAudioFrame &frame = m_frames.back();
frame.parseHeader(m_reader, diag);
// parse frames until the first non-empty frame is reached
auto isFrameEmpty = false;
while (!isFrameEmpty && m_frames.size() < 200) {
MpegAudioFrame &frame = m_frames.emplace_back();
frame.parseHeader(m_reader, diag);
isFrameEmpty = frame.size();
if (frame.isProtectedByCrc()) {
m_istream->seekg(2, ios_base::cur);
}
}
const MpegAudioFrame &frame = m_frames.back();
addInfo(frame, *this);
if (frame.isXingBytesfieldPresent()) {
std::uint32_t xingSize = frame.xingBytesfield();
if (m_size && xingSize != m_size) {
diag.emplace_back(DiagLevel::Warning,
"Real length of MPEG audio frames is not equal with value provided by Xing header. The Xing header value will be used.", context);
"Real length of MPEG audio frames is not in accordance with value provided by Xing header. The Xing header value will be used.",
context);
m_size = xingSize;
}
}