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// Copyright 2019 The libgav1 Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "examples/file_reader.h"
#include <algorithm>
#include <cstdint>
#include <cstdio>
#include <new>
#include <string>
#include <vector>
#if defined(_WIN32)
#include <fcntl.h>
#include <io.h>
#endif
#include "examples/file_reader_constants.h"
#include "examples/file_reader_factory.h"
#include "examples/file_reader_interface.h"
#include "examples/ivf_parser.h"
#include "examples/logging.h"
namespace libgav1 {
namespace {
FILE* SetBinaryMode(FILE* stream) {
#if defined(_WIN32)
_setmode(_fileno(stream), _O_BINARY);
#endif
return stream;
}
} // namespace
bool FileReader::registered_in_factory_ =
FileReaderFactory::RegisterReader(FileReader::Open);
FileReader::~FileReader() {
if (owns_file_) fclose(file_);
}
std::unique_ptr<FileReaderInterface> FileReader::Open(
const std::string& file_name, const bool error_tolerant) {
if (file_name.empty()) return nullptr;
FILE* raw_file_ptr;
bool owns_file = true;
if (file_name == "-") {
raw_file_ptr = SetBinaryMode(stdin);
owns_file = false; // stdin is owned by the Standard C Library.
} else {
raw_file_ptr = fopen(file_name.c_str(), "rb");
}
if (raw_file_ptr == nullptr) {
return nullptr;
}
std::unique_ptr<FileReader> file(
new (std::nothrow) FileReader(raw_file_ptr, owns_file, error_tolerant));
if (file == nullptr) {
LIBGAV1_EXAMPLES_LOG_ERROR("Out of memory");
if (owns_file) fclose(raw_file_ptr);
return nullptr;
}
if (!file->ReadIvfFileHeader()) {
LIBGAV1_EXAMPLES_LOG_ERROR("Unsupported file type");
return nullptr;
}
// With C++11, to return |file|, an explicit move is required as the return
// type differs from the local variable. Overload resolution isn't guaranteed
// in this case, though some compilers may adopt the C++14 behavior (C++
// Standard Core Language Issue #1579, Return by converting move
// constructor):
// https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1579
// To keep things simple we opt for the following compatible form.
return std::unique_ptr<FileReaderInterface>(file.release());
}
// IVF Frame Header format, from https://wiki.multimedia.cx/index.php/IVF
// bytes 0-3 size of frame in bytes (not including the 12-byte header)
// bytes 4-11 64-bit presentation timestamp
// bytes 12.. frame data
bool FileReader::ReadTemporalUnit(std::vector<uint8_t>* const tu_data,
int64_t* const timestamp) {
if (tu_data == nullptr) return false;
tu_data->clear();
uint8_t header_buffer[kIvfFrameHeaderSize];
const size_t num_read = fread(header_buffer, 1, kIvfFrameHeaderSize, file_);
if (IsEndOfFile()) {
if (num_read != 0) {
LIBGAV1_EXAMPLES_LOG_ERROR(
"Cannot read IVF frame header: Not enough data available");
return false;
}
return true;
}
IvfFrameHeader ivf_frame_header;
if (!ParseIvfFrameHeader(header_buffer, &ivf_frame_header)) {
LIBGAV1_EXAMPLES_LOG_ERROR("Could not parse IVF frame header");
if (error_tolerant_) {
ivf_frame_header.frame_size =
std::min(ivf_frame_header.frame_size, size_t{kMaxTemporalUnitSize});
} else {
return false;
}
}
if (timestamp != nullptr) *timestamp = ivf_frame_header.timestamp;
tu_data->resize(ivf_frame_header.frame_size);
const size_t size_read =
fread(tu_data->data(), 1, ivf_frame_header.frame_size, file_);
if (size_read != ivf_frame_header.frame_size) {
LIBGAV1_EXAMPLES_LOG_ERROR(
"Unexpected EOF or I/O error reading frame data");
if (error_tolerant_) {
tu_data->resize(size_read);
} else {
return false;
}
}
return true;
}
// Attempt to read an IVF file header. Returns true for success, and false for
// failure.
//
// IVF File Header format, from https://wiki.multimedia.cx/index.php/IVF
// bytes 0-3 signature: 'DKIF'
// bytes 4-5 version (should be 0)
// bytes 6-7 length of header in bytes
// bytes 8-11 codec FourCC (e.g., 'VP80')
// bytes 12-13 width in pixels
// bytes 14-15 height in pixels
// bytes 16-19 frame rate
// bytes 20-23 time scale
// bytes 24-27 number of frames in file
// bytes 28-31 unused
//
// Note: The rate and scale fields correspond to the numerator and denominator
// of frame rate (fps) or time base (the reciprocal of frame rate) as follows:
//
// bytes 16-19 frame rate timebase.den framerate.numerator
// bytes 20-23 time scale timebase.num framerate.denominator
bool FileReader::ReadIvfFileHeader() {
uint8_t header_buffer[kIvfFileHeaderSize];
const size_t num_read = fread(header_buffer, 1, kIvfFileHeaderSize, file_);
if (num_read != kIvfFileHeaderSize) {
LIBGAV1_EXAMPLES_LOG_ERROR(
"Cannot read IVF header: Not enough data available");
return false;
}
IvfFileHeader ivf_file_header;
if (!ParseIvfFileHeader(header_buffer, &ivf_file_header)) {
LIBGAV1_EXAMPLES_LOG_ERROR("Could not parse IVF file header");
if (error_tolerant_) {
ivf_file_header = {};
} else {
return false;
}
}
width_ = ivf_file_header.width;
height_ = ivf_file_header.height;
frame_rate_ = ivf_file_header.frame_rate_numerator;
time_scale_ = ivf_file_header.frame_rate_denominator;
type_ = kFileTypeIvf;
return true;
}
} // namespace libgav1
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