Implement Running Godot as Movie Writer

* Allows running the game in "movie writer" mode.
* It ensures entirely stable framerate, so your run can be saved stable and with proper sound (which is impossible if your CPU/GPU can't sustain doing this in real-time).
* If disabling vsync, it can save movies faster than the game is run, but if you want to control the interaction it can get difficult.
* Implements a simple, default MJPEG writer.

This new features has two main use cases, which have high demand:
* Saving game videos in high quality and ensuring the frame rate is *completely* stable, always.
* Using Godot as a tool to make movies and animations (which is ideal if you want interaction, or creating them procedurally. No other software is as good for this).

**Note**: This feature **IS NOT** for capturing real-time footage. Use something like OBS, SimpleScreenRecorder or FRAPS to achieve that, as they do a much better job at intercepting the compositor than Godot can probably do using Vulkan or OpenGL natively. If your game runs near real-time when capturing, you can still use this feature but it will play no sound (sound will be saved directly).

Usage:

$ godot --write-movie movie.avi [scene_file.tscn]

Missing:

* Options for configuring video writing via GLOBAL_DEF
* UI Menu for launching with this mode from the editor.
* Add to list of command line options.
* Add a feature tag to override configurations when movie writing (fantastic for saving videos with highest quality settings).

1 files changed, 73 insertions, 0 deletions

diff --git a/servers/movie_writer/movie_writer_mjpeg.h b/servers/movie_writer/movie_writer_mjpeg.h
new file mode 100644
index 0000000000..822bedfedf
--- /dev/null
+++ b/servers/movie_writer/movie_writer_mjpeg.h
@@ -0,0 +1,73 @@
+/*************************************************************************/
+/*  movie_writer_mjpeg.h                                                 */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef MOVIE_WRITER_MJPEG_H
+#define MOVIE_WRITER_MJPEG_H
+
+#include "servers/movie_writer/movie_writer.h"
+
+class MovieWriterMJPEG : public MovieWriter {
+	GDCLASS(MovieWriterMJPEG, MovieWriter)
+
+	uint32_t mix_rate = 48000;
+	AudioServer::SpeakerMode speaker_mode = AudioServer::SPEAKER_MODE_STEREO;
+	String base_path;
+	uint32_t frame_count = 0;
+	uint32_t fps = 0;
+	float quality = 0.75;
+
+	uint32_t audio_block_size = 0;
+
+	Vector<uint32_t> jpg_frame_sizes;
+
+	uint64_t total_frames_ofs = 0;
+	uint64_t total_frames_ofs2 = 0;
+	uint64_t total_frames_ofs3 = 0;
+	uint64_t total_audio_frames_ofs4 = 0;
+	uint64_t movi_data_ofs = 0;
+
+	Ref<FileAccess> f;
+
+protected:
+	virtual uint32_t get_audio_mix_rate() const override;
+	virtual AudioServer::SpeakerMode get_audio_speaker_mode() const override;
+	virtual void get_supported_extensions(List<String> *r_extensions) const override;
+
+	virtual Error write_begin(const Size2i &p_movie_size, uint32_t p_fps, const String &p_base_path) override;
+	virtual Error write_frame(const Ref<Image> &p_image, const int32_t *p_audio_data) override;
+	virtual void write_end() override;
+
+	virtual bool handles_file(const String &p_path) const override;
+
+public:
+	MovieWriterMJPEG();
+};
+
+#endif // MOVIE_WRITER_AVIJPEG_H