Only2try   Posted at 2019-12-23 20:40:07(260Wks ago) Report Permalink URL | ||
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| Before starting and showing you why I decided to switch to opus, here is a brief description taken from the official website: https://opus-codec.org/ Opus is a totally open, royalty-free, highly versatile audio codec. Opus is unmatched for interactive speech and music transmission over the Internet, but is also intended for storage and streaming applications. It is standardized by the Internet Engineering Task Force (IETF) as RFC 6716 which incorporated technology from Skype’s SILK codec and Xiph.Org’s CELT codec. Opus can handle a wide range of audio applications, including Voice over IP, videoconferencing, in-game chat, and even remote live music performances. It can scale from low bitrate narrowband speech to very high quality stereo music. Supported features are: Bitrates from 6 kb/s to 510 kb/s Sampling rates from 8 kHz (narrowband) to 48 kHz (fullband) Frame sizes from 2.5 ms to 60 ms Support for both constant bitrate (CBR) and variable bitrate (VBR) Audio bandwidth from narrowband to fullband Support for speech and music Support for mono and stereo Support for up to 255 channels (multistream frames) Dynamically adjustable bitrate, audio bandwidth, and frame size Good loss robustness and packet loss concealment (PLC) Floating point and fixed-point implementation ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ In my first post I will analyze some screenshots that show the acoustic spectrum of an audio sample, which has been converted into different formats to verify the quality of Opus audio against that of common formats such as Ogg Vorbis, mp3, wma & m4a (aac). Important notes on Opus: 1. The bitrate at which it is set is not shown; 2. Unlike other audio formats, the frequency reaches up to 24 kHz. As a first sample we have Ogg Vorbis  Keep in mind that I set the Vorbis to 256 kbps, so don't worry if its sprint doesn't remain stable on 20 kHz, instead it makes you feel shocked as Opus manages to do it at that bitrate at which it is set, which is only 128 kbps! 8o As a second sample we have mp3 (lame) set at 320 bitrate  In this image you can see that Opus manages to keep up, or be better in my view, than an mp3 set at its maximum bitrate. Here is the difference seen in the image  The third sample is instead set at a bitrate of 192 kbps, just to show how the most common audio formats react if we begin to lower the bitrate to a certain threshold, here is the turn of the wma  needless to highlight the differences since they are so obvious The last sample is set to bitrate 256, like the first one and is m4a  If I'm honest, the m4a really surprised me, because even if it's not set at 320 kbps, it manages to have a "scary" spectrum. Now for the inexperienced in the matter, like me, there is a question we can ask. So seen this sample why not use m4a as an audio format? 1. I, the undersigned, hate commercial software and everything connected to it, so I am always looking for what I love, that is, free software; 2. The fact that the m4a exceeds 20 kHz is not an incentive for its use, as experts have proven that the human ear can only listen up to 20 kHz at maximum (usually lower than that), and furthermore listening to music such as FLAC on devices with poor audio output quality, such as a smartphone or systems that are not Hi-fi, is really useless; 3. Having an excellent acoustic spectrum at a low bitrate, I found this format perfect for sharing audio files; 4. It was developed to be suitable for both real-time interactive applications via the Internet and for archiving audio files. Opus incorporates technologies from the SILK and low latency CELT speech codecs. Opus can perfectly adapt to high and low transmission speeds and can be used both as a codec for speech and for natural sounds. It also has a very low algorithmic delay compared to the most popular music formats such as mp3, Vorbis and HE-AAC and has often proved to be better both in terms of quality ratio and transmission speed. Okay, the test ends here, and I hope you enjoyed it as my first real forum post, but before I conclude the post, follow other screenshots showing the other formats competing at different bitrates.   ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Tests carried out thanks to the use of the following website and software: https://picturegalaxy.org/ http://spek.cc/ https://www.linux-apps.com/p/1126634/ Using for Opus its plugin, installable from terminal for Debian diastro and derivatives (MX Linux, Linux Mint, Ubuntu, and more) with the command: sudo apt install opus-tools Last edited by Only2try on 2021-01-06 14:36:40 | |
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Alien4 Posted at 2020-01-09 02:45:14(257Wks ago) Report Permalink URL | ||
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| I remember a good few years back Bubanee started tinkering with opus on his audio uploads, not to everyone's taste as I remember you could rip a cd to opus using dbpoweramp cd ripper (I think) can't quite remember as I no longer have any of the encoding tools I used to use back at ET and other sites.......... Long live FLAC!!! But on my movie rips I generally used dvdfab to rip and mkv - ac3 or dts audio :P :D Last edited by Alien4 on 2020-01-09 02:47:45 | |
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