psidtopgm

Convert the image data in a PS file to a PGM image of the specified dimensions and quality

$ psidtopgm [width] [height] [bits_per_sample] [path/to/file.ps] > [path/to/image.pgm]

psidtopgm [options]

    The input PSID file.


    The output PGM file.

-h
    Display help message.

-v
    Verbose output.

-s
    Set sample rate (default: 44100). For example -s 22050

-l
    Set length in seconds. For example -l 5

The `psidtopgm` command is a utility that converts PSID (PlayStation 1 ID) music files into the PGM (Portable Graymap) audio data format. It extracts the audio data from a PSID file and outputs it in a raw, uncompressed PGM format suitable for further processing or analysis.
The generated PGM file can be used to visualize the audio waveform or for other audio processing tasks. Keep in mind that PGM, in this context, isn't a true image format but rather represents audio samples as grayscale data. It's a rather niche tool primarily used by developers and audio enthusiasts working with PlayStation 1 audio.

The generated PGM file is not a standard image file. It represents the audio samples as grayscale values, and it requires a specialized viewer or further processing to interpret it as audio. The PSID file must be in a valid format.

The PGM file produced by `psidtopgm` represents the audio waveform. Each row in the PGM file corresponds to a single audio sample. The grayscale value of each pixel represents the amplitude of the audio sample at that point in time.
Black represents the minimum amplitude, while white represents the maximum amplitude. Gray represents a zero or mid-point amplitude.
To convert the PGM back into audio you would need to decode it back into raw audio samples and play them using a program like aplay.

The command likely originated within the demoscene or homebrew PlayStation 1 development communities where PSID files are often used for storing music. Its development was driven by the need to extract and analyze audio data from these files. Information on the specific author and earliest versions are hard to find as this command is part of much bigger projects, such as libsidplayfp. It's been maintained by contributors to the libsidplayfp library.

sidplayfp(1), xmpdump(1)