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Table of Contents

1. Running the encoder
2. Sample command lines
3. Common and important command lines
4. How to make Encoding faster

Running the encoder

This section describes how to run the encoder application aomenc from the command line, including descriptions of the most commonly used input parameters and outputs.

The sample application typically takes the following command line parameters:

Basic Usage: aomenc <options> -o dst_filename src_filename

src_filename is a Y4M file (e.g. 8 bit 4:2:0 planar) containing the video sequence that will be encoded.

The Y4M File can be obtained with e.g. ffmpeg (ffmpeg -i input.mp4 -r 24000/1000 -pix_fmt yuv420p output.y4m) Another option would be directly piping through ffmpeg to aomenc: ffmpeg -i "input.mkv" -pix_fmt yuv420p -f yuv4mpegpipe - | aomenc.exe -

-o dst_filename is the resulting video output of the encoder. The container is typically ivf. E.g. output.ivf

Sample command lines

2-Pass ABR 10bit @23.976fps

1st Pass: aomenc.exe --passes=2 --pass=1 --width=1920 --height=1080 --bit-depth=10 --fps=24000/1001 --target-bitrate=250 --fpf=stats.log --output=NUL input.y4m

2nd Pass: aomenc.exe --passes=2 --pass=2 --width=1920 --height=1080 --bit-depth=10 --fps=24000/1001 --target-bitrate=250 --fpf=stats.log --output=out.ivf input.y4m

1-Pass Constant Quality 10bit @23.976fps

aomenc.exe --passes=1 --bit-depth=10 --fps=24000/1001 --end-usage=q --cq-level=20 --output=out.ivf input.y4m

Common and important command lines

Command Line	Description
--help	Show usage options and exit
--output=arg	Output filename
--passes=arg	Number of passes (1/2)
--pass=arg	Pass to execute (1/2)
--fpf=arg	First pass statistics file name
--width=arg	Frame width
--height=arg	Frame height
--fps=arg	Stream frame rate (rate/scale) e.g. 24000/1001 = 23.976
--bit-depth=arg	Bit depth (8, 10, 12)
--end-usage=arg	Rate control mode (vbr, cbr, cq, q)
--target-bitrate=arg	Bitrate (kbps)
--cq-level=arg	Constant/Constrained Quality level
--cpu-used=arg	CPU Used (0..5) - Speed/Quality Setting - Recommended: 3 - 0 = slowest - 5 = fastest
--tile-columns=arg	Number of tile columns to use, log2
--tile-rows=arg	Number of tile rows to use, log2
--aq-mode=arg	Adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3: cyclic refresh)

<options> All Encoder Options can be found with --help

How to make Encoding faster

Due to the ultra slow encoding, many people would ask themself, how to improve the encoding time.

Here are some thoughts, commands and facts:

1. --cpu-used=arg The cpu-used setting is a speed setting. With lower Values you get slower encoding but better quality. With higher speeds you get faster encoding but worse quality. Recommended: 3 (Range: 0-5)
2. --tile-columns=arg and --tile-rows=arg - these settings split the video-image into columns and rows. Higher values may improve multi-threading capability and encoding speed, but the video quality decreases and the resulting file size is bigger.
3. Instead of splitting the video-image into pieces, it's also possible to cut the video file into chunks, encode them parallel and Concatenate them later. ffmpeg Concatenate The Resulting size may be a little bit bigger, due the fact it may place more I-Frames. But the difference is pretty small, thus this option being a good way for longer videos.