Video Encoding and Transcoding Quiz

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Questions and Answers

What is the purpose of a demuxer in the transcoding process?

To prepare the encoded data packets

To record the output file

To separate audio and video streams (correct)

To encode the audio

Which option accurately describes the functionality of the command 'ffmpeg -i {input} {output}'?

This command encodes the input into a different format. (correct)

This command filters the input file.

This command exchanges audio and video tracks.

This command captures a video stream from a device.

Which encoding library is known for providing the highest quality audio?

libopus (correct)

libvorbis

libmp3lame

libfdk_aac

What does the CRF option control during video encoding?

The quality of the video Signup and view all the answers

In the laws of encoding, what is the trade-off described for fast encoding?

It leads to a large file size and low quality. Signup and view all the answers

Which command will change the duration of a video?

-t {hrs}:{mins}:{secs}.{msecs} Signup and view all the answers

Which audio library is associated with Dolby Digital encoding?

ac3 Signup and view all the answers

Which statement about small file size encoding is correct?

It results in small files but poor quality. Signup and view all the answers

What type of video format is NDI primarily associated with?

Network Device Interface Signup and view all the answers

Which of the following specifications allows for high-definition video delivery over a computer network?

NDI Signup and view all the answers

Which audio format is NOT typically supported by standard DVD-Video?

MS-ADPCM Signup and view all the answers

What resolution format is standard for DVD-Video?

720x576 Signup and view all the answers

Which of the following is a characteristic of Blu-Ray Discs compared to standard DVDs?

Uses a blue laser for reading Signup and view all the answers

Which digital TV standard is used primarily in Japan and South America?

ISDB Signup and view all the answers

What is a notable difference between DVB-T and DVB-T2?

DVB-T2 accommodates multiple channels in a single stream Signup and view all the answers

Which of the following compression algorithms is used by NDI HX2?

H.265 Signup and view all the answers

Which audio feature is NOT commonly supported in Blu-Ray Discs?

MP2 Signup and view all the answers

What is the storage capacity of a standard dual-layer DVD?

8.5 GB Signup and view all the answers

Which MPEG standard was developed in 2003 and is known for Advanced Video Coding?

MPEG-4 part 10 Signup and view all the answers

What is the main purpose of the D frames in MPEG-1 part 2?

To serve as low-quality frames for preview during scrubbing Signup and view all the answers

Which codec family did Google acquire in 2010 that includes VP8 and VP9?

On2 Signup and view all the answers

Which standard is used by Blu-ray discs?

MPEG-2 part 2 Signup and view all the answers

What is the maximum resolution specified for MPEG-2 part 2?

1920×11522 Signup and view all the answers

Which of the following codecs is known for being used mainly in games and was renamed from The Duck Corporation?

VP3 Signup and view all the answers

What video coding standard was released in 2020 and is referred to as MPEG-I Part 3?

H.266 Signup and view all the answers

The VP8 codec is associated with which RFC number?

RFC6386 Signup and view all the answers

What is a disadvantage of SW encoders?

They are not suitable for devices with battery limitations. Signup and view all the answers

Which of the following is a characteristic of hybrid encoders?

They provide a workaround for older devices' limitations. Signup and view all the answers

What distinguishes HW encoders from SW encoders?

HW encoders involve fixed-function ASIC chips. Signup and view all the answers

Which API is specifically designed for video encoding on Nvidia graphics cards?

NVENC Signup and view all the answers

What is the main purpose of SMPTE ST 2110 standards?

To facilitate the transmission of AV over IP networks. Signup and view all the answers

Which of the following best describes the function of Quick Sync?

It provides fast video encoding but at a lower quality. Signup and view all the answers

What technological component do HW encoders primarily rely on?

Application-specific integrated circuits (ASICs). Signup and view all the answers

Which of the following statements about SDI is accurate?

SDI transmits audio, video, and timecode in a single direction. Signup and view all the answers

What is the purpose of switching from DVB-T to DVB-T2 in the Czech Republic?

To enhance service quality and channel availability Signup and view all the answers

In which scenario is a SW encoder preferred over a HW encoder?

When immediate availability of encoding resources is critical. Signup and view all the answers

Which of the following protocols is considered an open standard for streaming over HTTP?

MPEG Dynamic Adaptive Streaming over HTTP (DASH) Signup and view all the answers

What is the primary focus of the Digital Cinema Initiatives (DCI)?

To define specifications for digital cinema Signup and view all the answers

Which video resolution is associated with 4K in digital cinema?

4096×2160 Signup and view all the answers

What feature does HbbTV provide in hybrid TV services?

Access to internet services through TV Signup and view all the answers

What is FFMPEG primarily used for?

Encoding, decoding, and editing multimedia Signup and view all the answers

When did the switch to DVB-T begin in the Czech Republic?

2005 Signup and view all the answers

Which audio format is commonly used in RTP for live streaming?

AAC Signup and view all the answers

What is the primary characteristic of progressive scanning in digital video?

Draws all lines of each frame in sequence. Signup and view all the answers

Which aspect ratio is considered standard for HD television?

16:9 Signup and view all the answers

What is the function of shutter speed in video production?

Controls the time exposure of each frame. Signup and view all the answers

Which video compression method exploits redundancy between frames?

Inter-frame compression Signup and view all the answers

What is HDR video primarily characterized by?

Enables higher brightness levels than 100 cd/m². Signup and view all the answers

Which standard is specifically known for supporting SDR UHDTV with wider color gamut?

Rec. 2020 Signup and view all the answers

In video coding, what does an 'I-frame' represent?

An intra frame that can decode without references. Signup and view all the answers

What does the term 'bit-depth' refer to in digital video?

The number of bits used for each color component of a pixel. Signup and view all the answers

What is one of the main limitations of using 8-bit color depth in video?

It limits the range of color representation. Signup and view all the answers

Which of the following statements accurately describes 'motion vectors'?

They represent pieces that moved since the last keyframe. Signup and view all the answers

What is the implication of the transition from lossy to lossless video compression?

Lossless compression requires more storage space. Signup and view all the answers

What is the maximum frame rate typically considered for standard motion pictures?

24 fps Signup and view all the answers

Which of the following statements about '3D Video' is true?

It is purely a 2D representation. Signup and view all the answers

Study Notes

Digital Video

Film/TV/video is a sequence of images creating the illusion of motion.
Film is a motion picture art form and medium, approximately 130 years old, initially using film reels, now digital.
Video uses electronic mediums, including television broadcasting. Video or film does not always include sound.
Film is often used vertically in cinema, unlike in photography (except IMAX).
Film's positive qualities include its use in cinemas, and its grain (the random optical texture). The random texture arises from small particles of metallic silver or dye.
Film can be difficult to store due to damage from fire and mold. It's often archived by national film archives.
Digitalization of film involves scanning for both audio and video.

Video in 2020

Video streaming held a 57.64% traffic share in 2020.
YouTube held a 15.94% traffic share.
Netflix held an 11.42% traffic share.
Audio comprised 0.39%, the smallest percentage.

Youtube

Over 5 billion videos are available.
Over 500 hours of videos are uploaded daily.
Over 2 billion registered users.

Netflix

192.95 million subscribers
1.1 billion hours of daily viewings
Approx. 5600 shows

Other Streaming Services

HBO Max, HBO Now
Amazon Prime Video
Disney+
Hulu
TV broadcasts

Framerate

Frames per second are the number of frames per second in a video.
A higher frame rate equates to smoother motion as less strain on the brain.
Film uses 24 fps. PAL TV uses 25/50 fps, NTSC TV uses 29.97/59.94 fps.

Progressive, Interlaced, Pulldown Scan

Progressive format shows all image lines sequentially.
Interlaced displays image fields with odd and even lines alternately; it's more realistic.
Pulldown Scan slows down the film to 29.97 to match the TV rate.

Traditional Analog Television

Odd lines are displayed, then even lines. Only half the number of image frames are used.

High Frame Rate(HFR)

HFR has a motion picture standard of 24 fps.
In 1992 Momentum IMAX HD used 48 fps.
In 2012 Billy Lynn's Long Halftime Walk used 120 fps in 4K, 3D format.
DCI recommends 96 and 120 fps in 2D, 4K, and 3D
HFR is a higher frame rate than prior practice.

Shutter Speed

Shutter speed is the time used for the exposure of a single frame.
Synchronization with the frame rate is most effective for smoothness of motion in a video.
The amount of exposure is measured as an angle.
Shutter speed and frame rate are interlinked. The shutter is open during one frame time duration (1/frame rate).

Aspect Ratio

Ratio between width and height
silent film(4:3)
Talkies 1.375:1—academy ratio; later, 4:3 because sound track was wider; later in movies 1.78 or 16:9 was used to increase the wider vision to the viewer.
TVs and Digital Video—4:3, 16:9 for HD and UHD with cameras of ratio of 17:9;
21:9, monitored in some smartphones.
Photography(still)—3:2

Bit-depth

Number of bits used to present the color of a pixel
Professional video use 8, 10, 12-bit.
8-bit, 256 colours; 12-bit, 4096 colours.

Rec. 709

Standard for SDR HDTV image encoding and signal characteristics.
Succeeded Rec. 601 in digital recording of interlaced/analog video.
1920x1080p/i
23.976 - 60 fps
8-bit and 10-bit colour depth
35.9% of all colours for colour space

Rec. 2020

Standard for UHDTV, specifies SDR/UHDTV with WCG.
Adds new properties for the colour space

SDR Video

Standard dynamic range video with maximum brightness of 100 cd/m2.
8-bit, 6 stops and 10-bit, has 10 stops.
SD, HD, and UHD video and resolutions do not affect SDR quality.
Still good for streamings in 480p
HD is high-definition video.

HDR Video

High dynamic range video with higher brightness levels than SDR.
Enables higher brightness than 100 cd/m2.

EOTF and OETF

Electro-optical transformation function.
EOTF, input signal to linear light (output display)
Describes how digital data changes to light.
PQ, Perceptual quantizer
HLG, hybrid log-gamma
Backward compatible to SDR format

PQ and Metadata Standards

Nonlinear transformation functions for motion pictures.
Up to 10000 nits, up to 28 stops with HDR10, static metadata

HLG

Open standard without royalties
Backwards compatible with SDR devices.
Suitable for TV broadcasts.
Uses a gamma curve similar to SDR.

3D Video

Not really 3D, just 2D videos.
Older 3D employed anaglyph glasses (polarized or active shutter).
Today's 3D uses either polarization or active shutter.

HDCP

Protection against piracy with all devices in the video signal flow.
Support up to the version 2.2. Backwards compatible to older version.
More devices in the flow may increase bug probability

Compression Principles

Reduction of spatial and temporal video redundancy.
Intra uses frame-to-frame compression; It's less time-consuming.
Inter involves frame-to-frame data compression using motion information and data from previous frames.

Lossy Video Compression

Data reduction occurs between successive frames.
Temporal changes are only recorded, forward, and backward motion compensation using prediction error.
Less data is required because of better prediction
intra frame codecs: MJPEG-JPEGs; Prores; Cinema DNG; DN*HD

GOP

Group of Pictures, series of frames between two I-frames.
Distance between I-frames define the GOP
The I-frame is the least compressible.
P-frames are less compressible than I-frames.
B-frames are the most compressible, compared to I or P-frames.

Video Coding Formats and Standards

Sets of ecnoding/decoding capabilities for devices
Algorithms, bit-depth, and subsampling levels
Maximum resolution and bitrate enabling releases of cheaper HW.

Professional Coding Formats

Apple ProRes, White Paper, proprietary lossy codec, only I-frames, .mov, 8K resolution, 4:4:4, 10-12 bit.16-bit alpha.
Avid DNxHD/DNXHR, a lossy, high-resolution, post-production codec, HD-ST 2019-1: 2008 VC-3.

ProRes RAW

For post-production, in white paper. De-bayering necessary for 12+ bit depth (RAW, RAW HQ). Metadata is related to ISO, shutter speed, scene and take, as in Atoms recorders.

Blackmagic RAW

More modern, open-source, 12k, 12-bit raw recording.

Delivery Coding Formats

Groups of experts like MPEG and VCEG create proprietary standards for coding video, images, audio, and more.
ITU-T VCEG
MPEG-1 part 2; MPEG-2 part 2 with macroblocks
MPEG-4 part 10 with macroblocks.

VPX Family (Video Codec Family)

A collection of video codecs, like Theora, VP3, VP4-VP8, and VP9.

ISO/IEC 11172-2(MPEG-1 part 2)

Used for VCD, DVD, and DVD-Video, 1616 macroblocks, 88 blocks, many video profiles and 4 levels.
Used for DVB-T/S, DVD-Video, HDV, XDCAM, and Blu-Ray.

ITU-T H.262/MPEG-2 Part 2

16x16 macroblocks or 8x8 blocks; multi-view profile for 3D.
7 profiles and 4 levels.

ITU-T H.264/MPEG 4 Part 10

Standard for advanced video coding
16x16 macroblocks and 16x16-8x8 blocks.
Multiview coding (interlaced). 22 profiles and 20 levels

ITU-T H.265/MPEG-H Part 2, High Efficiency Video Coding (HEVC)

64x64 CTUs; supports quadtree or Quadtree structure.
Uses MVC, monochrome, HDR, and WCG for many profiles and 2 tiers.
Uses 8192x4320, 120 fps, 4:4:4, 16-bit.
Supports DVB-T2, UHD Blu-ray, Netflix.
Codecs like x265, SVT-HEVC, Kvazaar, OpenHevc, Turing, and DivX, Nero, MainConcept.

VP8, VP9, AV1

royalty free video coding formats, VP8, VP9, AV1, Open Media
16x16 or 4x4 macroblocks with Hadamard for DCT transformation
65536 x 65536, ∞ fps, and 4:2:2 or 8-bit to 12-bit.

Network Device Interfaces (NDI)

Software solution for delivering high-quality video over a computer network.
Supports a low-latency, frame-accurate delivery format.
Royalty-free license for use.

Video Distribution

Protocols for live streaming like DASH, and HLS, use HTTP for delivery.

DVD Video

Digital Versatile Disc, successor of VCD and SVCD.
4.7GB (single) layers, up to 17GB (double).
Supports 720x576 (D1), interlaced, MPEG-2, 9.8Mb/s
Subtitles, menus, chapters, limited interactivity.
Locked to 9 Regions.

Blu-ray Disc

Uses a blue laser and has standards managed by the Blu-ray Disc Association.
Supports 3D video, but does not use this often.

History of TV

Mechanical TV in 2nd half of the 19th century up to approx 100 lines.
Gray scale and analog TV in the 1970's and 50's, up to 625 lines for PAL, NTSC, SECAM.
Early 90's, colour analog HDTV and Japan developed in the 90's.

Digital TV Standards

4 main standards worldwide:
DVB (Europe)
ATSC (USA)
ISDB (Japan) and
DTMB (China)

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Description

Test your knowledge on video encoding and transcoding concepts. This quiz covers various aspects including demuxers, the ffmpeg command, audio libraries, and quality control during encoding. Perfect for those looking to deepen their understanding of multimedia processing.