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Sturdy Butterfly
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Testing and Issues

You can test this entry and submit issues during the testing period of the VoIP Contest, Round 1 contest.

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Voting

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Comments

Sturdy Butterfly Oct 28, 2019 at 11:56
tgvoipcall doesn't depend on ffmpeg or any other big libraries, using libopusfile to read and libogg to write opus files. Input/output to libtgvoip are using -DTGVOIP_USE_CALLBACK_AUDIO_IO, which makes it possible to run as many instances of tgvoipcall as needed on a single machine.

tgvoiprate uses Google's ViSQOL algorithm (https://link.springer.com/article/10.1186/s13636-015-0054-9) with some modifications, rewritten in C++. According to Google, this outperforms PESQ used by other entries.
6
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Issues

Fair Wombat Nov 14, 2019 at 11:06
The submitted tgvoiprate app got a score of 956 and took the 10th place in the scoring table, receiving 3⭐️.
External dependency: Google's ViSQOL algorithm (free license) -0.15⭐️
Final result is 2.85⭐️
10
Sleek Eagle Oct 29, 2019 at 04:03
This is not a good idea for encoding and writing data to an ogg file inside a blocking callback in a single thread - encoding and ogg_page_streamout can take a lot of time, especially in the case of variable data rates (https://xiph.org/ogg/doc/libogg/ogg_stream_pageout. HTML).
The receive cycle is locked until the page is written - so it increases the temporal latency and you loose some data. You must exit this handler as soon as it possible to not affect receiving process - save data to the buffer(pipe) which is being processed by asynchronous task.
Debian GNU/Linux 10
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Sturdy Butterfly Oct 29, 2019 at 11:47
You'd be right if I was using a real audio device, but knowing how callbacks are implemented in libtgvoip, I have up to 20 ms to do whatever I want in that callback, including writing a file.
B
Borik Bobrujskov Oct 28, 2019 at 14:45
Your tgvoiprate very often report 1.000000 status on a generated by your application ogg outputs (on all success calls (31 calls) I see only one non 1.000000 rate). This is because you loose some data while writing ogg files
Debian GNU/Linux 10 \n \l
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Sturdy Butterfly Oct 28, 2019 at 15:09
Try a longer file maybe? This might as well be a libtgvoip issue.
Fair Wombat Nov 12, 2019 at 11:47
Didn't find any copyrights for code or license information about ViSQOL alorithm.
Debian GNU/Linux 10 (buster)
Sturdy Butterfly Nov 12, 2019 at 19:22
The C++ implementation provided here is my own. The Matlab implementation I used as my primary reference can be found in various github repositories, for example here https://github.com/wireapp/wire-audio-video-signaling/tree/1e90bf464279f1915c87246622c58093811f10bf/test/audio_test/visqolrelease. This Matlab implementation is the only one I was able to find, and there's no license attached to it. There also are no restrictions in the research paper I linked in my comment. There are no patents mentioned anywhere either.

The research paper itself allows doing basically anything as long as you link to it, which I did in my comment:
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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