--- name: "yuvscaler" section: "1" platform: "linux" package: "mjpegtools" version: "2.2.1-4" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/yuvscaler" --- # yuvscaler(1) UPscales or DOWNscales a YUV4MPEG2 stream to a specified format ## NAME yuvscaler - UPscales or DOWNscales a YUV4MPEG2 stream to a specified format ## SYNOPSIS **yuvscaler** \[**-I** *input\_keyword*\] \[**-M** *mode\_keyword*\] \[**-O** *output\_keyword*\] \[**-n p**\|**s**\|**n**\] \[**-v 0**-**2**\] \[**-h**\] ## DESCRIPTION **yuvscaler** is a general (UP or DOWN) scaling utility that is provided to allow conversion between different video formats. It reads in a YUV4MPEG2 format stream from stdin (such as that produced by **lav2yuv**) and outputs such stream to stdout (e.g. to be consumed by **mpeg2enc**). The most common use of yuvscaler is to generate input suitable for MPEG encoding to VCD or SVCD formats using [**mpeg2enc**(1)](/mpeg2enc/1.md). **yuvscaler** will automatically take into account PAL/SECAM and NTSC format, as well as widescreen (16:9) format and interlacing. Use of yuvscaler was designed to be straightforward. ## EXAMPLES **VCD encoding:**\ lav2yuv my-file.avi \| yuvscaler -O VCD \| mpeg2enc -f 1 -o vcd.%d.m1v **SVCD encoding:**\ lav2yuv my-file.qt \| yuvscaler -O SVCD \| mpeg2enc -f 4 -o svcd.%d.m2v **Encoding anamorphic 16:9 as letterboxed VCD:**\ lav2yuv my-ana16-9.eli \| yuvscaler -M WIDE2VCD \| mpeg2enc -f 1 -o letterbox\_vcd.%d.m1v **Encoding anamorphic 16:9 as letterboxed SVCD:**\ lav2yuv my-ana16-9.eli \| yuvscaler -M WIDE2STD -O SVCD \| mpeg2enc -f 4 -o letterbox\_svcd.%d.m2v **Encoding anamorphic 16:9 as letterboxed DVD:**\ lav2yuv my-ana16-9.eli \| yuvscaler -M WIDE2STD -O DVD \| mpeg2enc -f 8 -o letterbox\_dvd.%d.m2v ## OPTIONS - **-I *input\_keyword*** - Specifies input processing options. Input options may be combined by using multiple **-I** flags. Possible *input\_keyword*s are: - **USE\_WidthxHeight+WidthOffset+HeightOffset** to select a useful area of the input frame (all multiple of 2, Height and HeightOffset multiple of 4 if interlaced), the rest of the image being discarded - **ACTIVE\_WidthxHeight+WidthOffset+HeightOffset** to select an active area of the input frame (all multiple of 2, Height and HeightOffset multiple of 4 if interlaced), the rest of the image being made black - **-M *mode\_keyword*** - Sets the scaling mode options. Scaling mode options can be combined by giving several **-M** flags. Possible are: - **BICUBIC** - to use the (Mitchell-Netravalli) high-quality bicubic upsacling and/or downscaling algorithm - **RESAMPLE** - to use a classical resampling algorithm -only for downscaling- that goes much faster than bicubic. For coherence reason, **yuvscaler** will use RESAMPLE if only downscaling is necessary, BICUBIC if not. - **WIDE2STD** - convert widescreen anamorphic (16:9) input video into letterboxed (4:3), generating necessary black lines. Note that for MPEG applications if your *player* can properly decode anamorphic video you may wish to leave the video unscaled and simply specify the approprate format during MPEG encoding (see [**mpeg2enc**(1)](/mpeg2enc/1.md)). - **RATIO\_WidthIn\_WidthOut\_HeightIn\_HeightOut** to specified scaling ratios of WidthIn/WidthOut for width and HeightIN/HeightOut for height to be applied to the useful area. The output frames that result from scaling can have a different format than the output format specified using **-O** options(s). In this case, **yuvscaler** automatically generate necessary black lines and columns and/or skips necessary lines and columns to center the scaled image in the output frame. - **WIDE2VCD** to scale anamorphic widescreen (16:9) frames into letterboxed VCD format (equivalent to -M WIDE2STD -O VCD). - **FASTVCD** to transcode full sized frames to VCD (equivalent to -M RATIO\_2\_1\_2\_1 -O VCD, see below). - **FAST\_WIDE2VCD** to transcode full-sized anamorphic (16:9) frames to letter-boxed VCD (equivalent to -M WIDE2STD -M RATIO\_2\_1\_2\_1 -O VCD, see below). - **NO\_HEADER** to suppress stream header generation on output - **MMX** to use MMX functions for BICUBIC scaling (experimental feature!!) - - **-O *output\_keyword*** - Sets the output frame format options. Output format options can be combined by giving several **-O** flags. By default, output frames size will be the same as input frame sizes, as well as output frames interlacing if coherent with output keyword specification which prevails, top\_first if not. - **MONOCHROME** to generate monochrome frames on output. Chrominance information for the scaled pixels is set neutral (white). MPEG encoding of black and white video will be both inefficient *and* show annonying chrominance artifacts unless this is done. - **VCD** to generate VCD compliant frames on output (taking care of PAL and NTSC standards). Non-interlaced output. - **SVCD** to generate SVCD compliant frames on output (taking care of PAL and NTSC standards). Top-field-first interlaced frames. - **DVD** to generate DVD compliant frames on output (taking care of PAL and NTSC standards). Top-field-first interlaced frames. - **SIZE\_WidthxHeight** to generate frames of size WidthxHeight on output (multiple of 4) - If VCD, SVCD or DVD keywords are not used, output interlacing is taken of the same type as input. By default, output frames size will be the same as input frame size. - - **-n p\|s\|n** (usually not necessary) if norm could not be determined from data flux, specifies the OUTPUT norm for VCD/SVCD (p=pal,s=secam,n=ntsc). - **-v 0\|1\|2** Specifies the degree of verbosity: 0=quiet, 1=normal, 2=verbose/debug - **-h** Prints a summary of command line syntax. **Note:** The most useful downscaling ratios are handled using dedicated optimised scaling routines. They are: - RATIO\_WidthIn\_WidthOut\_2\_1 =\> Full-sized frame to VCD downscaling - RATIO\_3\_2\_1\_1 =\> Full-sized frame to SVCD downscaling - RATIO\_1\_1\_4\_3 =\> WIDE2STD downscaling mode - RATIO\_WidthIn\_WidthOut\_1\_1 =\> downscaling only concerns width, not height - RATIO\_1\_1\_HeightIn\_HeightOut =\> downscaling only concerns height, not width - RATIO\_2\_1\_2\_1 =\> FASTVCD, slightly width distorted (real ratio 45 to 22) but faster full-sized frame to VCD downscaling (-M RATIO\_2\_1\_2\_1 -O VCD) - RATIO\_WidthIn\_WidthOut\_8\_3 =\> specific to WIDE2VCD downscaling (-M WIDE2STD -O VCD) - RATIO\_2\_1\_8\_3 =\> specific to (slighly distorted) FAST\_WIDE2VCD downscaling (-M WIDE2STD -M RATIO\_2\_1\_2\_1 -O VCD) - RATIO\_1\_1\_1\_1 =\> copy useful input part of possible several files into output frames ## AUTHOR This man page was written by Xavier Biquard et al.\ If you have questions, remarks, problems or you just want to contact the developers, the main mailing list for the MJPEG-tools is:\ *mjpeg-users@lists.sourceforge.net* - For more info, see our website at *http://mjpeg.sourceforge.net/* ## SEE ALSO [**mjpegtools**(1)](/mjpegtools/1.md), [**lavpipe**(1)](/lavpipe/1.md), [**lav2yuv**(1)](/lav2yuv/1.md) [**mpeg2enc**(1)](/mpeg2enc/1.md)