Resizing Video with FFmpeg: Two Passes, Without Aspect Ratio, Without Black Borders
In this article, we will discuss how to resize a video using the FFmpeg tool, specifically using the two-pass method, without preserving the aspect ratio and without adding black borders. We will cover the key concepts, commands, and options needed to achieve this.
What is FFmpeg?
FFmpeg is a free and open-source tool that can be used for handling multimedia files, such as audio, video, and images. It is widely used in the multimedia industry for tasks such as format conversion, video editing, and streaming. FFmpeg is available for different platforms, including Windows, Linux, and macOS.
Two Passes Resizing
When resizing a video, it is recommended to use the two-pass method to ensure better quality and file size. In the two-pass method, the encoding process is divided into two steps: the first pass is used to analyze the video and calculate the optimal bitrate, while the second pass is used to encode the video using the bitrate calculated in the first pass.
Resizing Without Aspect Ratio
When resizing a video without preserving the aspect ratio, the width and height of the video are changed independently. This can result in a distorted image if the aspect ratio is not carefully considered. In this article, we will not preserve the aspect ratio, but we will make sure that the video does not have black borders.
Resizing Without Black Borders
When resizing a video without adding black borders, the output video will have the same size as the input video. This can be achieved by using the scale filter in FFmpeg. The scale filter can be used to change the dimensions of the video while keeping the aspect ratio.
Command Line Options
Here is an example of a command that can be used to resize a video using the two-pass method, without preserving the aspect ratio, and without adding black borders:
ffmpeg -y -i "G:\InputFile(1280x544).mp4" -map_chapters -1 -map_metadata -1 -vf "scale=-2:544" -c:v libx264 -b:v 1024k -pass 1 -f mp4 -This command uses the following options:
-y: overwrite output files without asking for confirmation-i: input file-map_chapters -1: ignore chapters-map_metadata -1: ignore metadata-vf: video filterchain (in this case, thescalefilter)-c:v: video codec (in this case,libx264)-b:v: video bitrate (in this case,1024k)-pass 1: first pass-f: output format (in this case,mp4)
After the first pass, we need to run the second pass using the following command:
ffmpeg -i input.mp4 -i input.log -vf "scale=-2:544" -c:v libx264 -b:v 1024k -pass 2 output.mp4In the second pass, we need to provide the input file, the log file from the first pass, and the same filterchain, codec, bitrate, and pass options.
In this article, we discussed how to resize a video using the FFmpeg tool, specifically using the two-pass method, without preserving the aspect ratio and without adding black borders. We covered the key concepts and command line options needed to achieve this. The final command line for resizing a video with the mentioned settings is:
ffmpeg -y -i "G:\InputFile(1280x544).mp4" -map_metadata -1 -vf "scale=-2:544" -c:v libx264 -b:v 1024k -pass 1 -f mp4 -
ffmpeg -i input.mp4 -i input.log -vf "scale=-2:544" -c:v libx264 -b:v 1024k -pass 2 output.mp4