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From the wiki page (https://wiki.vexatos.com/dfpwm): > DFPWM (Dynamic Filter Pulse Width Modulation) is an audio codec > created by Ben “GreaseMonkey” Russell in 2012, originally to be used > as a voice codec for asiekierka's pixmess, a C remake of 64pixels. > It is a 1-bit-per-sample codec which uses a dynamic-strength one-pole > low-pass filter as a predictor. Due to the fact that a raw DPFWM decoding > creates a high-pitched whine, it is often followed by some post-processing > filters to make the stream more listenable. It has recently gained popularity through the ComputerCraft mod for Minecraft, which added support for audio through this codec, as well as the Computronics expansion which preceeded the official support. These both implement the slightly adjusted 1a version of the codec, which is the version I have chosen for this patch. This patch adds a new codec (with encoding and decoding) for DFPWM1a. The codec sources are pretty simple: they use the reference codec with a basic wrapper to connect it to the FFmpeg AVCodec system. To clarify, the codec does not have a specific sample rate - it is provided by the container (or user), which is typically 48000, but has also been known to be 32768. The codec does not specify channel info either, and it's pretty much always used with one mono channel. However, since it appears that libavcodec expects both sample rate and channel count to be handled by either the codec or container, I have made the decision to allow multiple channels interleaved, which as far as I know has never been used, but it works fine here nevertheless. The accompanying raw format has a channels option to set this. (I expect most users of this will not use multiple channels, but it remains an option just in case.) This patch will be highly useful to ComputerCraft developers who are working with audio, as it is the standard format for audio, and there are few user-friendly encoders out there, and even fewer decoders. It will streamline the process for importing and listening to audio, replacing the need to write code or use tools that require very specific input formats. You may use the CraftOS-PC program (https://www.craftos-pc.cc) to test out DFPWM playback. To use it, run the program and type this command: "attach left speaker" Then run "speaker play <file.dfpwm>" for each file. The app runs in a sandbox, so files have to be transferred in first; the easiest way to do this is to simply drag the file on the window. (Or copy files to the folder at https://www.craftos-pc.cc/docs/saves.) Sample DFPWM files can be generated with an online tool at https://music.madefor.cc. This is the current best way to encode DFPWM files. Simply drag an audio file onto the page, and it will encode it, giving a download link on the page. I've made sure to update all of the docs as per Developer§7, and I've tested it as per section 8. Test files encoded to DFPWM play correctly in ComputerCraft, and other files that work in CC are correctly decoded. I have also verified that corrupt files do not crash the decoder - this should theoretically not be an issue as the result size is constant with respect to the input size. Signed-off-by: Jack Bruienne <jackbruienne@gmail.com> |
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| compat | ||
| doc | ||
| ffbuild | ||
| fftools | ||
| libavcodec | ||
| libavdevice | ||
| libavfilter | ||
| libavformat | ||
| libavutil | ||
| libpostproc | ||
| libswresample | ||
| libswscale | ||
| presets | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .travis.yml | ||
| Changelog | ||
| configure | ||
| CONTRIBUTING.md | ||
| COPYING.GPLv2 | ||
| COPYING.GPLv3 | ||
| COPYING.LGPLv2.1 | ||
| COPYING.LGPLv3 | ||
| CREDITS | ||
| INSTALL.md | ||
| LICENSE.md | ||
| MAINTAINERS | ||
| Makefile | ||
| README.md | ||
| RELEASE | ||
FFmpeg README
FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides means to alter decoded audio and video through a directed graph of connected filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements color conversion and scaling routines.
Tools
- ffmpeg is a command line toolbox to manipulate, convert and stream multimedia content.
- ffplay is a minimalistic multimedia player.
- ffprobe is a simple analysis tool to inspect multimedia content.
- Additional small tools such as
aviocat,ismindexandqt-faststart.
Documentation
The offline documentation is available in the doc/ directory.
The online documentation is available in the main website and in the wiki.
Examples
Coding examples are available in the doc/examples directory.
License
FFmpeg codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.
Contributing
Patches should be submitted to the ffmpeg-devel mailing list using
git format-patch or git send-email. Github pull requests should be
avoided because they are not part of our review process and will be ignored.