A1. Reformatting Audio Files Project

About ffmprovisr

Making FFmpeg Easier

FFmpeg is a powerful tool for manipulating audiovisual files. Unfortunately, it also has a steep learning curve, especially for users unfamiliar with a command line interface. This app helps users through the command generation process so that more people can reap the benefits of FFmpeg.

Each button displays helpful information about how to perform a wide variety of tasks using FFmpeg. To use this site, click on the task you would like to perform. A new window will open up with a sample command and a description of how that command works. You can copy this command and understand how the command works with a breakdown of each of the flags.

Change codec (transcode)

This command transcodes an input file into a deinterlaced Apple ProRes 422 LT file with 16-bit linear PCM encoded audio. The file is deinterlaced using the yadif filter (Yet Another De-Interlacing Filter).

ffmpeg

starts the command

-i input_file

path, name and extension of the input file

-c:v prores

tells FFmpeg to transcode the video stream into Apple ProRes 422

-profile:v 1

Declares profile of ProRes you want to use. The profiles are explained below:

• 0 = ProRes 422 (Proxy)
• 1 = ProRes 422 (LT)
• 2 = ProRes 422 (Standard)
• 3 = ProRes 422 (HQ)

-vf yadif

Runs a deinterlacing video filter (yet another deinterlacing filter) on the new file. -vf is an alias for -filter:v.

-c:a pcm_s16le

tells FFmpeg to encode the audio stream in 16-bit linear PCM

output_file

path, name and extension of the output file
The extension for the QuickTime container is .mov.

FFmpeg comes with more than one ProRes encoder:

• prores is much faster, can be used for progressive video only, and seems to be better for video according to Rec. 601 (Recommendation ITU-R BT.601).
• prores_ks generates a better file, can also be used for interlaced video, allows also encoding of ProRes 4444 (-c:v prores_ks -profile:v 4) and ProRes 4444 XQ (-c:v prores_ks -profile:v 5), and seems to be better for video according to Rec. 709 (Recommendation ITU-R BT.709).

Transcode to H.264

ffmpeg -i input_file -c:v libx264 -pix_fmt yuv420p -c:a aac output_file

This command takes an input file and transcodes it to H.264 with an .mp4 wrapper, audio is transcoded to AAC. The libx264 codec defaults to a “medium” preset for compression quality and a CRF of 23. CRF stands for constant rate factor and determines the quality and file size of the resulting H.264 video. A low CRF means high quality and large file size; a high CRF means the opposite.”

Source Links

Change codec/ Transcoding command line

Transcode to H.264

source: About ffimprovisr.