FFMPEG

Introduction

  • Acronym for Fast Forward Motion Picture Expert Group.
  • platform or structure for developing software applications.
  • able to process anything in terms of audio, video, data and pictures.
  • Encode - process of compressing a file so as to enable the faster transmission of the file.
  • Decode - function that translates encoded data into its original format.
  • Codec
    • enCOder, DECoder.
    • video codecs - MPEG, H.264, AV1
    • audio codecs - Mp3, AAC, Opus, ogg, vorbis, flac, alac
  • Bitrate
    • data rate, is the amount of data per second in the encoded video file, usually expressed in kilobits per secod(kps) or megabits per second(mbps)
    • mp3 - maximum bitrate of 320 kilobit per second.
    • standard CD - 1.411 kilobit per second
    • h264 video in FullHd has a bitrate in the range of 3.000 - 6.000kbps, while 4k can reach 51.000 kbps
    • non-compressed i.e Apple ProRes format in 4k can reach 253,900kbps.
  • Container
    • like a box contains important objects, containers exist to allow multiple data streams such as video, audio, subtitles and other data, to be embedded into a single file.
    • e.g mp4, mkv, webm, mov, mxf, asf, MPEG transfrom stream(.ts), Core Audio Format(.caf), webp
  • Mux
    • process of taking encoded data in the form of packets and write it into files in a specific container format
  • Demux
    • process of reading media files and split it into chunks of data.
  • Transmuxing
    • repackaging, packetizing
    • process in which audio and video files are repackaged into different delivery formats without changing original file content.
  • Transcoding
    • process of converting a media file or object from one format to another.
  • Resolution
    • defines the number of pixels that make up the picture on your screen.
    • TV resolution is defined as number of pixels contained vertically in the picture.
    • SD -480, HD - 720,1080, UHD - 2160, 4320 - 8K UHD.
  • Aspect Ratio
    • is the ratio of width to height of the TV screen.
    • certain spect ratios are designed to handle certain resolutions without stretching or distortion of picture without blank space around the picture.
    • 4:3, 16:9
  • Interlaced format
    • display a full picture by dividing it into 2 different set of lines: the even and the odd lines.
    • each are displayed on the screen every 1/60th of a second, both of which constitute a video frame.
    • earliest video compression method.
  • Progressive
    • displays both even and odd lines at the same time, entire video frame at the same time.
  • Letter box
    • is the practice of transferring film shot in a widescreen aspect ratio to standard width video formats while preserving the content original aspect ratio.
    • LBX, LTBX
  • VOD/SVOD
    • video on demand
    • Subscription video on demand
  • Streaming
    • process of delivering media through small chunks of compressed data and sent to a requesting device.
  • HLS
    • HTTP Live Streaming Protocol.
    • created by Apple for delivering video destined for Apple devices.
  • DASH
    • Dynamic Adaptive Streaming over Http
    • Open source HLS
  • M3U8
    • standard text file encoded utf-8 format and organized as a playlist of items with their location, to be reproduced in a particular sequence.
  • AV1
    • AOMedia - Alliance for Open Media Video 1
    • Ms, Amazon, Apple, Mozilla, Netflix, Google,Intel
  • HDR
    • High Dynamic Range
    • Recreate image realism from camera through post-production to display and distribution.
  • h264
    • standard for video compression defined by MPEG AND ITU.
    • h264/AVC