---
name: "pgmtoy4m"
section: "1"
platform: "linux"
package: "mjpegtools"
version: "2.2.1-4"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pgmtoy4m"
---

# pgmtoy4m(1)

Convert mpeg2dec pgm and pgmpipe output to YUV4MPEG2

## NAME

pgmtoy4m - Convert mpeg2dec pgm and pgmpipe output to YUV4MPEG2

## SYNOPSIS

**pgmtoy4m** \[*options*\]

## DESCRIPTION

**pgmtoy4m** repacks the PGM output from **mpeg2dec** into YUV4MPEG2 4:2:0p.    No actual changes to the data are made.  The data is unpacked from the quasi-PGM format and placed in YUV4MPEG2 format with the specified sample aspect, frame rate and field order. Output must be either to a pipe or a file, leaving stdout as a terminal will elicit an error and the program will exit.

## OPTIONS

**pgmtoy4m** accepts the following options:

- **-v** *num*

  Set verbosity level. (default: 0)

- **-h**

  Print a usage summary and exit.

- **-i** *t\|b\|p*

  Set the interlacing mode.  Top field first (t), bottom field first (b) or  progressive/none (p). (default: t)

- **-a** *sar*

  Set the sample aspect ratio.   (default: 10:11)

- **-r** *frame rate*

  Set the frame rate. (default: 30000:1001)

## EXAMPLES

```
mpeg2dec -s -o pgmpipe file.mpg | pgmtoy4m -a 10:11 -r 24000:1001 -i b | yuvplay

mpeg2dec -s -o pgm file.mpg
cat *.pgm | pgmtoy4m -r 30000:1001 -i t | yuvplay
```

## NOTES

This program is specifically designed to work with the output of mpeg2dec and is **NOT** a general PGM (NetPBM) tool!

From the introduction in the source file:

```
 * Note: mpeg2dec uses a variation of the PGM format - they're really not
 * "Grey Maps" but rather a catenation of the 420P data (commonly called
 * "YUV").    The type is P5 ("raw") and the number of rows is really
 * the total of the Y', Cb and Cr heights.   The Cb and Cr data is "joined"
 * together.  After the Y' rows you have 1 row of Cb and 1 row of Cr per
 * "row" of PGM data.
 * NOTE: You MAY need to know the field order (top/bottom field first),
 *      sample aspect ratio and frame rate because the PGM format makes
 *      none of that information available!
```

## AUTHOR

This manpage was written by Steven Schultz (sms at 2bsd dot com).

## BUGS

Possible but none known at the present time.