From 323f089a81b289473b2c70a9e8a7a30d805cc354 Mon Sep 17 00:00:00 2001 From: Cody Boone Ferguson <53008573+xexyl@users.noreply.github.com> Date: Fri, 21 Apr 2023 10:59:28 -0700 Subject: [PATCH] Updates and fixes in 2001/coupard Format fix README.md. Update .gitignore with file referenced by the author. --- 2001/coupard/.gitignore | 1 + 2001/coupard/README.md | 86 ++++++++++++++++++++++------------------- 2 files changed, 47 insertions(+), 40 deletions(-) diff --git a/2001/coupard/.gitignore b/2001/coupard/.gitignore index 04b0c16d3..7e1830c99 100644 --- a/2001/coupard/.gitignore +++ b/2001/coupard/.gitignore @@ -1 +1,2 @@ coupard +test.wav diff --git a/2001/coupard/README.md b/2001/coupard/README.md index a98e88a97..6e8e6ad11 100644 --- a/2001/coupard/README.md +++ b/2001/coupard/README.md @@ -1,11 +1,11 @@ # Most obfuscated sound - Pierre-Philippe Coupard - Lineo, Inc. - ATTN : Pierre-Philippe Coupard - 390 South 400 West - Lindon, UT 84042 - USA +Pierre-Philippe Coupard +Lineo, Inc. +ATTN : Pierre-Philippe Coupard +390 South 400 West +Lindon, UT 84042 +USA ## To build: @@ -27,9 +27,13 @@ make ``` If you're using macOS then you won't have these devices. If however you install -sox from MacPorts or Homebrew you can do something like: +[sox](https://en.wikipedia.org/wiki/SoX) from +[MacPorts](https://www.macports.org) or [Homebrew](https://brew.sh) you can do +something like: - ./coupard | sox -q -traw -r8000 -b8 -e unsigned-integer - -tcoreaudio +```sh +./coupard | sox -q -traw -r8000 -b8 -e unsigned-integer - -tcoreaudio +``` Thanks go to [Yusuke Endoh](/winners.html#Yusuke_Endoh) for providing a proper command line (see [/2013/endoh3/README.md](2013/endoh3/README.md). @@ -45,41 +49,42 @@ your arm or the wall for confirmation. Past years' IOCCC entries do many marvellous things in small packages, such as console utilities, games, math, languages or even X applications. But they all have one thing in common (despite being hard -to read obviously) : when they interact with the user, they only +to read obviously): when they interact with the user, they only *display* things, i.e. they display either text or drawings. So, for a change, this program titillates the sense of hearing instead -of sight : this program is a self-contained speech synthesizer that +of sight: this program is a self-contained speech synthesizer that tells the current time through the computer's sound card - in just under 2 Kb of source code ! -In the 2001 IOCCC rules and guidelines documents, there is no mention of -what is or isn't acceptable regarding audio I/Os, but it is mentioned +In the 2001 IOCCC [rules](/2001/rules.txt) and +[guidelines](/2001/guidelines.txt) documents, there is no mention of +what is or isn't acceptable regarding audio I/O, but it is mentioned that hardware-specific and/or non-portable programs are not welcome. So, in order to do audio and satisfy those requirements, the format required -by /dev/audio has been chosen : /dev/audio is a rather ancient +by `/dev/audio` has been chosen: `/dev/audio` is a rather ancient fixed-format audio interface that is supported by the majority of Unices -that can do sound, as a lowest-denominator sound I/Os interface. +that can do sound, as a lowest-denominator sound I/O interface. -### Program usage: +### Program usage -* To listen to what the program says directly, invoke +To listen to what the program says directly, invoke ```sh ./coupard > /dev/audio ``` -the program then speaks out something like +The program then speaks out something like "The time is HH hours MM minutes SS seconds" in military time (24 hours). Of course, you need to have permissions -to write to /dev/audio, have your sound card enabled, the volume up, +to write to `/dev/audio`, have your sound card enabled, the volume up, the speakers connected ... :-) -* If you want to convert the audio output of the program into another -audio format, you can pipe it to sox for example (sox is the -Swiss army knife of Unix audio tools) : the command +If you want to convert the audio output of the program into another audio +format, you can pipe it to [sox](https://en.wikipedia.org/wiki/SoX) for example +(`sox` is the Swiss army knife of Unix audio tools): the command: ```sh ./coupard | sox -c1 -r8000 -tub - -c2 -r44100 -twav test.wav @@ -90,28 +95,30 @@ file and saves it into "test.wav". The output format of the program is 8KHz, unsigned 8-bit samples. -NOTE : the program's return code is meaningless +NOTE: the program's return code is meaningless. -### Audio quality: +### Audio quality The quality of the sound produced by the program is cross between a -yogurt-pot-and-string telephone and a bad gramophone, i.e. the S/N -ratio is very low and the signal's top frequency is very low as well. -This is because the audio is stored internally at a sampling rate of -4KHz (the Nyquist frequency is only 2KHz) with only 4-bit samples -(adding 24db of quantization noise to an already poor signal). +yogurt-pot-and-string telephone and a bad gramophone, i.e. the S/N ratio is very +low and the signal's top frequency is very low as well. This is because the +audio is stored internally at a sampling rate of 4KHz (the [Nyquist +frequency](https://en.wikipedia.org/wiki/Nyquist_frequency) is only 2KHz) with +only 4-bit samples (adding 24db of quantization noise to an already poor +signal). In short, you might have to listen twice to understand what the program is saying. 2048 bytes including the sound generation program doesn't leave much room for audio quality ;-) -### Speech generation: +### Speech generation Only 9 phonemes are used to generate the speech. Beside the limited number of words the program has to generate (66 words), the low sound quality is actually exploited to take liberties with certain consonants (for example, "s" and "f" sound very much the same at 4KHz, -so they can be merged into one phoneme). Because the psychoacoustic +so they can be merged into one phoneme). Because the +[psychoacoustic](https://en.wikipedia.org/wiki/Psychoacoustics) context around those phonemes is just sufficient, the words can be interpreted correctly most of the time despite the fact that they are pronounced quite wrongly. @@ -120,7 +127,7 @@ Internally, a table is used to generate most of the words, and composite words such as "thirty-five" are made up by the C code externally. -### Data compression: +### Data compression Even at 4KHz / 4 bits, the weight of all the phoneme samples and the word-to-phonemes table put together is over 1600 bytes, which is well @@ -134,22 +141,21 @@ decompression code can't be made small enough. The best compression compromise was found using a simple Huffman compressor, and encoding the compressed data by blocks of 13 bits in -pairs of printable ASCII characters : the raw data is compressed to +pairs of printable ASCII characters: the raw data is compressed to 8465 bits, and the resulting C string is therefore about 1300 characters, which leaves just enough room for the decompressor with a hard-coded Huffman tree, and the code that plays the phonemes in the right order. -### Note on compiler warnings and lint: +### Note on compiler warnings and lint -The program should build with gcc's -Wall -Werror and -ansi flags. If -the -pedantic flag is used, gcc will complain about the length of the -data string and the sign of its type, and also the fact that main() -returns with no value. The confusion with the sign of the char type -doesn't matter with the data string because it's composed only of -printable characters under 127. +The program should build with `gcc -Wall -Werror -ansi`. If the `-pedantic` +flag is used, gcc will complain about the length of the data string and the sign +of its type, and also the fact that `main()` returns with no value. The +confusion with the sign of the char type doesn't matter with the data string +because it's composed only of printable characters under 127. -When linting the program with lclint, it complains about a huge list +When linting the program with `lclint`, it complains about a huge list of things that, if corrected to make lint happy, would probably double the size of the source code.