The very most important digital video properties

according to Ashley Blewer,

a/v archivist and software developer

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01

Hey there

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MediaInfo

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Properties

The usual introduction

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What is that?

What are important details to know about video?

01

Hey there

Who is this?

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Ashley Blewer

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Worked on MediaConch, QCTools, & other media analysis tools for archivists

Lots of stuff to learn about here: https://ashleyblewer.com

Ashley Blewer

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Worked on MediaConch, QCTools, & other media analysis tools for archivists

Lots of stuff to learn about here: https://ashleyblewer.com

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https://archivesoftomorrow.com

@ablwr online

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Let's go, MediaInfo

metadata extraction tool

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Why MediaInfo?

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• Robust format support
• Robust data
• Versatile
• Works everywhere
• Open source
• Microservice
• Easy to use

Wide format support

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Matroska (mkv/mka/mks)

Ogg (ogg/ogm)

Riff (avi/wav)

Mpeg 1&2 container (mpeg/mpg/vob)

Mpeg 4 container (mp4)

Mpeg video specific (mpgv/mpv/m1v/m2v)

Mpeg audio specific (mp2/mp3)

Windows Media (asf/wma/wmv)

Quicktime (qt/mov)

Real (rm/rmvb/ra)

DVD-Video (ifo)

AC3 (ac3)

DTS (dts)

AAC (aac)

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Monkey's Audio (ape/mac) Flac (flac)

CDXA, like Video-CD (dat)

Apple/SGI (aiff/aifc)

Sun/NeXT (au)

Amiga IFF/SVX8/SV16 (iff)

Ensoniq PARIS (paf)

Sound Designer 2 (sd2)

Berkeley/IRCAM/CARL (irca)

SoundFoundry WAVE 64 (w64)

Matlab (mat)

Portable Voice format (pvf)

FastTracker2 Extanded (xi)

Midi Sample dump Format (sds)

Audio Visual Research (avr)

fun fact

MediaConch

MediaInfo works underneath MediaConch to do media analysis

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MediaInfo streams

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General: Title, author, director, album, track number, date, duration

Video: codec, aspect ratio, framerate, bitrate

Audio: codec, sample rate, channels, language, bitrate

Text: subtitle language

Chapters: numbers of chapters, list of chapters

MediaInfo streams

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Container: format, profile, commercial name of the format, duration, overall bit rate, writing application and library, title, author, director, album, track number, date, duration, et cetera

Video: format, codec id, aspect, frame rate, bit rate, color space, chroma subsampling, bit depth, scan type, scan order, et cetera

Audio: format, codec id, sample rate, channels, bit depth, language, bit rate, et cetera

Text: format, codec id, language of subtitle, et cetera

Chapters: count of chapters, list of chapters, et cetera

Versatile

Command Line

GUI (graphical user interface)

Online

Programming bindings

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Also: open source! ✨✨✨

BSD-2-Clause License

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Audio/Video properties

thinking in streams

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MediaInfo streams: General

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• Unique ID : string
• Complete name : new_file.mkv
• Format : Matroska
• Format version : Version 4 / Version 2
• File size : 1.16 MiB
• Duration : 10 s 0 ms
• Overall bit rate : 977 kb/s
• Writing application : Lavf57.83.100
• Writing library : Lavf57.83.100
• ErrorDetectionType : Per level 1

MediaInfo streams: Video (Pt 1)

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• ID : 1
• Format : FFV1
• Format version : Version 0
• Codec ID : V_MS/VFW/FOURCC / FFV1
• Duration : 10 s 0 ms
• Width : 720 pixels
• Height : 576 pixels
• Display aspect ratio : 5:4
• Frame rate mode : Constant
• Frame rate : 25.000 FPS
• Standard : PAL

MediaInfo streams: Video (Pt 2)

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• Color space : YUV
• Chroma subsampling : 4:2:0
• Bit depth : 8 bits
• Compression mode : Lossless
• Writing library : Lavc57.107.100 ffv1
• Default : Yes
• Forced : No
• DURATION : 00:00:10.000000000
• coder_type : Golomb Rice

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MediaInfo streams: Audio

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• ID : 2
• Format : PCM
• Codec ID : A_PCM/INT/LIT
• Duration : 10 s 0 ms
• Bit rate mode : Constant
• Channel(s) : 1 channel
• Sampling rate : 48.0 kHz
• Bit depth : 16 bits
• Writing library : Lavc57.107.100 pcm_s16le
• Default : Yes
• Forced : No
• DURATION : 00:00:10.000000000

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Audio/Video properties

(for real this time)

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Containers and Codecs

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• Container: the General stream
• Muxing/demuxing
• Codec: the Video and Audio streams
• Encoding/decoding

Containers and Codecs

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source: ffmpeg docs

Containers vs Codecs

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• Just some notes:
• container and codec can have the same name
• not all containers/codecs can work together
• (See this chart: https://en.wikipedia.org/wiki/Comparison_of_video_container_formats)
• additionally: sometimes their properties can clash with each other

Containers

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• aka "Wrapper"
• usually just that – contains some significant information but usually fairly light

MediaInfo streams: General

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• Unique ID : string
• Complete name : new_file.mkv
• Format : Matroska
• Format version : Version 4 / Version 2
• File size : 1.16 MiB
• Duration : 10 s 0 ms
• Overall bit rate : 977 kb/s
• Writing application : Lavf57.83.100
• Writing library : Lavf57.83.100
• ErrorDetectionType : Per level 1

Codecs

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• Here's where most of the trouble can be found
• Uncompressed / compressed
• Lossy / lossless
• "perceptually" lossless is a marketing scam
• Open / closed
• Codec profiles (e.g. h.264)

MediaInfo streams: Video (Pt 1)

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• ID : 1
• Format : FFV1
• Format version : Version 0
• Codec ID : V_MS/VFW/FOURCC / FFV1
• Duration : 10 s 0 ms
• Width : 720 pixels
• Height : 576 pixels
• Display aspect ratio : 5:4
• Frame rate mode : Constant
• Frame rate : 25.000 FPS
• Standard : PAL

MediaInfo streams: Video (Pt 1)

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• ID : 1
• Format : FFV1
• Format version : Version 0
• Codec ID : V_MS/VFW/FOURCC / FFV1
• Duration : 10 s 0 ms
• Width : 720 pixels
• Height : 576 pixels
• Display aspect ratio : 5:4
• Frame rate mode : Constant
• Frame rate : 25.000 FPS
• Standard : PAL

MediaInfo streams: Video (Pt 1)

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• Width & Height
• Depending on codec, may need to be divisible by an even number

MediaInfo streams: Video (Pt 1)

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• Display Aspect Ratio
• Pixel Aspect Ratio
• Storage Aspect Ratio

MediaInfo streams: Video (Pt 1)

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• Standard
• Just PAL, NTSC, SECAM – you probably have been learning about this already because it comes from legacy analog standards

MediaInfo streams: Video

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• Frame rate
• You also probably know a bit about this already – this is worth keeping an eye on because it can make things a bit weird, esp. during conversions
• Frames are straightforward but time is not

MediaInfo streams: Video (Pt 2)

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• Color space : YUV
• Chroma subsampling : 4:2:0
• Bit depth : 8 bits
• Compression mode : Lossless
• Writing library : Lavc57.107.100 ffv1
• Default : Yes
• Forced : No
• DURATION : 00:00:10.000000000
• coder_type : Golomb Rice

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MediaInfo streams: Color space

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Color space

* How is color organized, translated, conveyed, and presented?

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MediaInfo streams: Chroma subsampling

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Chroma subsampling

Some common ones for preservation (because we want the best):

• 4:4:4 (not actually subsampling)
• 4:2:2 (this is broadcast standard)
• 4:2:0 (also common in production)

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MediaInfo streams: Chroma subsampling

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• 4:4:4, 4:2:2, 4:2:0

x:y:z

x = width (horizontal) of sample size

y = number of chroma samples in the first row

z = number of chroma samples in the second row

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MediaInfo streams: Bit depth

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Bit depth

* Can think of this as "color depth"

* Represents depth of each color (RGB, YUV)

* 8bit, 10bit, and beyond

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MediaInfo streams: Audio

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• ID : 2
• Format : PCM
• Codec ID : A_PCM/INT/LIT
• Duration : 10 s 0 ms
• Bit rate mode : Constant
• Channel(s) : 1 channel
• Sampling rate : 48.0 kHz
• Bit depth : 16 bits
• Writing library : Lavc57.107.100 pcm_s16le
• Default : Yes
• Forced : No
• DURATION : 00:00:10.000000000

MediaInfo streams: Audio channels

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Channels

* Can represent positions (surround sound setup)

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MediaInfo streams: Audio sampling rate

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Sampling rate

* the "frames" of audio

* higher is better

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MediaInfo streams: Audio bit depth

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Bit depth

* another quality indicator

* bits of information in each sample

bits - 1s and 0s

sample - value in time

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And many more!

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Those are some of the bigger audio/video properties you'll encounter, with tons of nuance and more complex details

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What else do you want to know about?

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Thank youuu

More questions?

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ashley.blewer@gmail.com

ashleyblewer.com

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