ref: 219c645fe7cd8398f84a031862808ea9e0040bf0
dir: /pplay.man/
.TH PPLAY 1 .SH NAME pplay \- visual PCM audio player and editor .SH SYNOPSIS .B audio/pplay [ .B -Dcs ] [ .B pcmfile ] .SH DESCRIPTION .I Pplay is a PCM audio player which shows a time-domain graphical plot of the data and allows for some simple editing operations. It operates on the same format used by the audio device (see .IR audio (3)). .PP At startup, all input data is loaded in its entirety into memory, either from .B pcmfile if provided, or from standard in. It then writes samples to .BR /dev/audio , unless .B -c is specified. .SS "Command line parameters" .TF "pcmfile" .TP .B -c Turn verbose debugging info on .TP .B -c Write audio to standard out instead of .B /dev/audio .TP .B -s Draw right channel's waveform as well .TP .B pcmfile Read file instead of standard in .PD .SS "Keyboard and mouse commands" Key commands: .TF "=" .TP .B q Quit .TP .B ␣ Toggle play/pause .TP .B b Jump to loop start .TP .B = Zoom in .TP .B - Zoom out .TP .B + Fine zoom in .TP .B _ Fine zoom out .TP .B ↵ Zoom into the entire dot .TP .B z Reset zoom to entire buffer .TP .B ← Pan left by screenful .TP .B → Pan right by screenful .PD .PP Mouse buttons: .TF "1 " .TP .B 1 Set cursor .TP .B 2 Set left or right dot bound .TP .B 3 Pan view horizontally .PD .SS "Dot and cursor position" .I Pplay loops an interval, referred to as the .IR dot , indefinitely. The current position (cursor) in the buffer is shown by an orangle vertical line, which can be set by clicking with the left mouse button anywhere within the dot. The dot is set by default to the entire file, and is shown by two vertical grey lines on either side of the cursor. With the middle mouse button, the left or right bound is set depending on whether a middle mouse button click occurred resp. on the left or on the right of the cursor. The cursor may never escape the dot. .SS "Display" The graphical plot shows the maximal and minimal sample value among the pixels packed in each pixel column, by default for the left channel only. .PP A line of status text on the bottom left of the graphical view displays timing information, the cursor and the dot, in number of .I samples rather than bytes. It is of the form: .TF "__n" .TP .BI T\ n Number of samples per pixel column .TP .BI @\ n Time in hh:mm:ss.tt format (see .IR tmdate (2) .TP .BI ( n ) Absolute cursor position in number of samples .TP .BI ·\ n Left bound of the dot .TP .BI ↺\ n Right bound of the dot, or .B ∞ if unbounded .PD .PP By default, the entire buffer is displayed, spanning the width of the window. The y axis spans the entire range of possible of a sample, with positive values above the midpoint. .SS "Editing" Commands: .TF "r file" .TP .BI <\ cmd Pipe output of a shell command replacing dot or inserting at the cursor (∗) .TP .BI ^\ cmd Pipe dot to a shell command and read back its output into dot .TP .BI |\ cmd Pipe dot to a shell command .TP .B c Set snarf buffer to the contents of the dot (‡) .TP .B d Cut dot, replacing snarf buffer (‡) .TP .B p Paste snarf buffer into dot or insert at the cursor (∗) .TP .BI r\ file Read file into dot or at the cursor (∗) .TP .B s Show dot by piping it to a new .IR pplay (1) instance .TP .B u Undo an edit and dot change .TP .BI w\ file Write dot to file .TP .B x Crop to dot (exclusive cut); does .B not touch the snarf buffer (‡) .PD .PP Upon typing a key not part of the set of keyboard shortcuts, a text entry appears to enter commands in. Commands are single character codes, and all following text is used as an arguments list. .PP Editing is performed either on the dot, its complement (everything excluding the dot), or at the position of the cursor if the dot is in its default state. Operations are entirely decomposable into a series of one or more insertions or deletions .RI ( indels ). Insertions place new data at an offset from the start, either the left bound of the dot if set, or the cursor's position. Deletions act on and thus require a valid dot, smaller than the size of the buffer. Commands above marked with a star (∗) change their behavior depending on whether the dot is set or not; those marked with a dagger (‡) always require a valid dot. .PP The .I u (undo) command reverts a single indel and restores the dot as it were before. In other words, complex operations that are a series of several indels require multiple .I undo commands to be unrolled completely. .I Undo is not infinite and there currently is no .I redo implementation. .PP Commands .BR < ,\ ^\ and\ | need a valid .IR rc (1) expression, which is then passed uninterpreted. In other words, expressions such as: .IP .EX |stretch -r1.2 | norm -f 2 | audio/wavenc > seymourbutz.wav .EE .PP will be passed as a single string to and evaluated in a subshell, with the dot written to its standard in. File i/o commands .BR r ,\ w prompt for a pathname which is also uninterpreted. Consequently, commands and i/o may fail once actually executed; in case .I pplay was reading from a file or pipe, the partial content already loaded will not be discarded. .SS Memory management No data loaded into memory is ever freed unless it can be guaranteed to never be used again. While refcounting is already being done, currently no attempt to keep guarantees is made and nothing is ever freed. However, memory is never duplicated. Therefore, it is dangerous to load large amounts of data, but once loaded, memory usage will not grow much. .SH EXAMPLES Use .IR play (1) to decode any known audio format: .IP .EX ; play -o /fd/1 file | audio/pplay .EE .SH "SEE ALSO" .IR audio (1), .IR play (1), .IR rc (1), .IR audio (3) .SH HISTORY .I Pplay first spawned on 9front (October, 2017), beyond the environment. .SH BUGS Drawing halts while playback is paused. .PP Mousing, in particular for panning, can be uncomfortable or annoying. .PP There are no safeguards against races when writing to file. .PP The data structure implementation underlying the editing commands is, despite much effort to the contrary, still prone to off-by-ones and other bugs. Trust, but save often. .PP Any unintended interruption in playback due to scheduling, or slower than instaneous redraws, are considered bugs, and drawing ones are still there -- crawling, slithering, glistening in the dark, poisoning my dreams and turning them into nightmares.