jmarya/knowledge
jmarya/knowledge
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

restructure

Browse source
This commit is contained in:
JMARyA 2024-01-17 09:00:45 +01:00
parent ef7661245b
commit 598a10bc28
Signed by: jmarya
GPG key ID: 901B2ADDF27C2263
182 changed files with 342 additions and 336 deletions
Download patch file Download diff file Expand all files Collapse all files

20
technology/files/media/audio/FLAC.md Normal file
View file

@ -0,0 +1,20 @@
---
repo: https://gitlab.xiph.org/xiph/flac
website: https://xiph.org/flac/
obj: codec
---
# FLAC
FLAC (Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, developed by the Xiph.Org Foundation, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size and decompresses to an identical copy of the original audio data.
FLAC is an open format with royalty-free licensing and a reference implementation which is free software. FLAC has support for metadata tagging, album cover art, and fast seeking.
| Name | Value |
| --------------- | --------------------------------- |
| Initial Release | 2001-07-20 |
| Repository | https://gitlab.xiph.org/xiph/flac |
| Website | https://xiph.org/flac/ |
## Comparison to other formats
FLAC is specifically designed for efficient packing of audio data, unlike general-purpose lossless algorithms such as DEFLATE, which are used in [ZIP](../../ZIP.md) and gzip. While [ZIP](../../ZIP.md) may reduce the size of a CD-quality audio file by 10–20%, FLAC is able to reduce the size of audio data by 40–50% by taking advantage of the characteristics of audio.
The technical strengths of FLAC compared to other lossless formats lie in its ability to be streamed and decoded quickly, independent of compression level.
Since FLAC is a lossless scheme, it is suitable as an archive format for owners of CDs and other media who wish to preserve their audio collections. If the original media are lost, damaged, or worn out, a FLAC copy of the audio tracks ensures that an exact duplicate of the original data can be recovered at any time. An exact restoration from a lossy copy (e.g., MP3) of the same data is impossible. FLAC being lossless means it is highly suitable for transcoding e.g. to MP3, without the normally associated transcoding quality loss between one lossy format and another. A CUE file can optionally be created when ripping a CD. If a CD is read and ripped perfectly to FLAC files, the CUE file allows later burning of an audio CD that is identical in audio data to the original CD, including track order and pregap, but excluding CD-Text and other additional data such as lyrics and CD+G graphics.

17
technology/files/media/audio/Opus.md Normal file
View file

@ -0,0 +1,17 @@
---
website: https://opus-codec.org/
obj: codec
---
# Opus
Opus is a lossy audio coding format developed by the Xiph.Org Foundation and standardized by the Internet Engineering Task Force, designed to efficiently code speech and general audio in a single format, while remaining low-latency enough for real-time interactive communication and low-complexity enough for low-end embedded processors. Opus replaces both Vorbis and Speex for new applications, and several blind listening tests have ranked it higher-quality than any other standard audio format at any given bitrate until transparency is reached, including MP3, AAC, and HE-AAC.
Opus combines the speech-oriented LPC-based SILK algorithm and the lower-latency MDCT-based CELT algorithm, switching between or combining them as needed for maximal efficiency. Bitrate, audio bandwidth, complexity, and algorithm can all be adjusted seamlessly in each frame. Opus has the low algorithmic delay (26.5 ms by default) necessary for use as part of a real-time communication link, networked music performances, and live lip sync; by trading-off quality or bitrate, the delay can be reduced down to 5 ms. Its delay is exceptionally low compared to competing [codecs](../Codecs.md), which require well over 100 ms, yet Opus performs very competitively with these formats in terms of quality per bitrate.
As an open format standardized through RFC 6716, a reference implementation called libopus is available under the New BSD License. The reference has both fixed-point and floating-point optimizations for low- and high-end devices, with SIMD optimizations on platforms that support them. All known software patents that cover Opus are licensed under royalty-free terms. Opus is widely used as the voice-over-IP (VoIP) codec in applications such as Discord, WhatsApp, and the PlayStation 4.
| Name | Value |
| --------- | ----------------------- |
| Extension | .opus |
| [MIME](../../MIME.md) | audio/ogg<br>audio/opus |
| Website | https://opus-codec.org/ |

10
technology/files/media/audio/WAV.md Normal file
View file

@ -0,0 +1,10 @@
---
obj: codec
---
# WAV
Waveform Audio File Format (WAVE, or WAV due to its filename extension; pronounced "wave") is an audio file format standard, developed by IBM and Microsoft, for storing an audio bitstream on PCs. It is the main format used on Microsoft Windows systems for uncompressed audio. The usual bitstream encoding is the linear pulse-code modulation (LPCM) format.
| Name | Value |
| --------- | -------------------------------------- |
| Extension | .wav<br>.wave |
| [MIME](../../MIME.md) | audio/x-wav<br>audio/wav<br>audio/wave |