88 lines
3.0 KiB
C++
88 lines
3.0 KiB
C++
// FFMPEG Video Encoder Integration for OBS Studio
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// Copyright (c) 2019 Michael Fabian Dirks <info@xaymar.com>
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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#include "h264.hpp"
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uint8_t* is_nal_start(uint8_t* ptr, uint8_t* end_ptr, size_t& size)
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{
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// Ensure that the remaining space actually can contain a prefix and NAL header.
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if ((ptr + (3 + 1)) >= end_ptr)
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return nullptr;
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if (*ptr != 0x0)
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return nullptr;
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if (*(ptr + 1) != 0x0)
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return nullptr;
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// 3-Byte NAL prefix.
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if (*(ptr + 2) == 0x1) {
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size = 3;
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return ptr + 3;
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}
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// 4-Byte NAL Prefix
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if ((ptr + (4 + 1)) >= end_ptr)
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return nullptr;
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if (*(ptr + 2) != 0x0)
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return nullptr;
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if (*(ptr + 3) != 0x01)
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return nullptr;
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size = 4;
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return ptr + 4;
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}
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uint8_t* streamfx::encoder::codec::h264::find_closest_nal(uint8_t* ptr, uint8_t* end_ptr, size_t& size)
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{
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for (uint8_t* seek_ptr = ptr; seek_ptr < end_ptr; seek_ptr++) {
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if (auto nal_ptr = is_nal_start(seek_ptr, end_ptr, size); nal_ptr != nullptr)
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return nal_ptr;
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}
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return nullptr;
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}
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uint32_t streamfx::encoder::codec::h264::get_packet_reference_count(uint8_t* ptr, uint8_t* end_ptr)
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{
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size_t nal_ptr_prefix = 0;
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uint8_t* nal_ptr = find_closest_nal(ptr, end_ptr, nal_ptr_prefix);
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while ((nal_ptr != nullptr) && (nal_ptr < end_ptr)) {
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// Try and figure out the actual size of the NAL.
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size_t nal_end_ptr_prefix = 0;
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uint8_t* nal_end_ptr = find_closest_nal(nal_ptr, end_ptr, nal_end_ptr_prefix);
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size_t nal_size = (nal_end_ptr ? nal_end_ptr : end_ptr) - nal_ptr - nal_end_ptr_prefix;
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// Try and figure out the ideal priority.
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switch (static_cast<nal_unit_type>((*nal_ptr) & 0x5)) {
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case nal_unit_type::CODED_SLICE_NONIDR:
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return static_cast<uint32_t>((*nal_ptr >> 5) & 0x2);
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case nal_unit_type::CODED_SLICE_IDR:
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return static_cast<uint32_t>((*nal_ptr >> 5) & 0x2);
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default:
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break;
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}
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// Update our NAL pointer.
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nal_ptr = nal_end_ptr;
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}
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return std::numeric_limits<uint32_t>::max();
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}
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