STR file format

Code example

STR playback library

This example will play a fullscreen STR file and is as straightforward as possible.
If you need more advanced control other the display size and position, see the STR playback library section.

@Lameguy64 has spent some time making a STR playback library that's easily included in a project :

One thing that I find somewhat missing here is a decent piece of code for playing STR video files easily. So, what I did was take the old and messy PsyQ STR player example, clean it up entirely, and finally make it into a cute little c library for easy implementation.

Original post :
Original download link :
Mirror :

Converting to AVI

Video dimensions

Note that your video's width and height must be multiples of 16, as the size of a MDEC decoded macroblock is 16x16.

You need AVI file 320x240, 15 fps, 24-bit color, Stereo 16-bit sound @ 44100 Hz.

Stream #0:0: Video: rawvideo, bgr24, 320x240, 27763 kb/s, 15 fps, 15 tbr, 15 tbn, 15 tbc
Stream #0:1: Audio: pcm_u8 ([1][0][0][0] / 0x0001), 44100 Hz, 2 channels, u8, 705 kb/s

Video to AVI

Use Virtualdub or ffmpeg+mencoder :

ffmpeg -i $INPUT.MKV -vcodec rawvideo -pix_fmt bgr24 -vf scale=320:240,setsar=1:1 -acodec pcm_u8 -ar 44100 -r 15 tmp.avi
mencoder tmp.avi -ovc copy -o $OUTPUT.avi 

If your video is upside down after using these commands, add the vflip filter to the ffmpeg's '-vf' section; i.e : -vf scale=320:240,setsar=1:1,vflip


Via the Graphic interface

Use MC32.EXE to convert the AVI file to STR using these settings :

Format : Input : Avi (Uncompressed), Output : str (MDEC)
Sound: 37.8 KHz, Stereo;
Easy: Double Speed, 15 fps, 1ch, Leap Sector;
MDEC: version 2


You should now have a new STR file and a new XA file in your folder. You have to interleave them in MC32 also:

Format : Input : str (MDEC), Output: str (MDEC)
Sound: Input: XA , 37.8 KHz, Stereo;
Frame rate: 15 fps, # Channels : 1(150sectors/s), Leap Sector;
CD-ROM speed : Double Speed;


Via the command line

MC32 can be used with a script to avoid using a graphical interface. The script syntax is described in PsyQ's documentation file 'Datavconv.pdf', p.34.

Here is an example script to convert a video + audio AVI file to STR+XA, then interleave them;

    path/to/input.avi,     # Input file name
    path/to/output.str,    # Output file name
    x2,                    # CD-ROM speed
    15fps,                 # Frame rate
    1,                     # Number of channels
    2,                     # MDEC version
    FALSE,                 # LeapSector (TRUE if source is video capture (59.94fps), FALSE if CG video (60FPS))
    37.8KHz,               # Frequency of Sound
    Stereo                 # Stereo or Mono

    path/to/input.str,    # Video file name
    strMDEC,              # Video format name
    path/to/input.xa,     # Sound file name
    path/to/output.str,   # Output file name (Sound & video)
    x2,                   # CD-ROM speed
    15fps,                # Frame rate
    1,                    # Number of channels
    FALSE,                # LeapSector (TRUE if source is video capture (59.94fps), FALSE if CG video (60FPS))
    FALSE,                # ver1.98 compatible leap sector
    37.8KHz,              # Frequency of Sound
    Stereo                # Stereo or Mono

Create a file with that content and save it with the scr extension; e.g : myscript.scr

You can then run this script with the following command :

mc32.exe -s myscript.scr

See here for a full reference of the scripting language :

MC32 manual has lots of information about the various encoding/interleaving settings :, p.14 to 58

MC32.EXE crashes

MC32 doesn't seem to like ffmpeg's AVI files and often crashes when hitting the 'Go' button. In order to prevent crashing, you should re-save the avi file with mencoder :

mencoder file.avi -ovc copy -o file_clean.avi 

You can also use virtualdub ; open the ffmpeg AVI file in virtualdub, then save it again ; File > Save as AVI... or F7 key, then retry.

Finding a video's frame count

With ffmpeg :

ffprobe -v error -select_streams v:0 -count_packets -show_entries stream=nb_read_packets -of csv=p=0 VIDEOFILE.AVI

Alternatively, open the STR file in MC32.exe and look at the bottom left of the window.

Tools & Refs

MC32 manual:, p.14 to 58

MC32 :
STR converter :

Original PsyQ sample code :

/psyq/addons/cd/MOVIE (same as /psx/sample/cd/MOVIE )

Original post :
Video to STR conversion tutorial :
MDEC notes :

Video credits

The video and song used in this example are by Nina Paley :