Unit no. 3Unit no. 3Digitizing Sound and VideoDigitizing Sound and Video

Adolf KnollAdolf Knoll

National Library of the Czech RepublicNational Library of the Czech Republic

adolf.knoll@nkp.czadolf.knoll@nkp.cz

Learning objectivesLearning objectives

After the completion of this unit the learner After the completion of this unit the learner will be able to:will be able to:

Understand the digital sound and the Understand the digital sound and the digital videodigital video

Apply basic solutions both for normal use Apply basic solutions both for normal use and archivingand archiving

Digitize correctly sound and video and Digitize correctly sound and video and make the most common products (VCD, make the most common products (VCD, SVCD, DVD Video, etc.)SVCD, DVD Video, etc.)

DigitDigitization of analogue audio and ization of analogue audio and videovideo

The analogue data in audio and video domains The analogue data in audio and video domains are most often are most often stored stored on these carriers:on these carriers: Magnetic tapes, be they in reels, audio cassettesMagnetic tapes, be they in reels, audio cassettes, ,

VHS, Video 8, and othersVHS, Video 8, and others Black shellac and vinyl discsBlack shellac and vinyl discs

These media can be replayed only on These media can be replayed only on appropriate replay devices (gramophone, video appropriate replay devices (gramophone, video cassette recorder/player, video cameras, etc.)cassette recorder/player, video cameras, etc.)

How to digitize them?How to digitize them?

The replay device must be connected to a The replay device must be connected to a conversion device:conversion device: Sound card in the computer for audio (Line-In Sound card in the computer for audio (Line-In

Connector)Connector) TV card or video chip that enables the conversion of TV card or video chip that enables the conversion of

the analogue video into the digital one (built-in or USB the analogue video into the digital one (built-in or USB connected to a computer, available in a digital video connected to a computer, available in a digital video recorder or camera, …)recorder or camera, …)

For data capture the software or utility must be For data capture the software or utility must be used that enable itused that enable it

Digitization of a vinyl disc

Analogue signalfrom the headphonesconnector

Line-In connectorof the sound card

Digitization of a Video 8analogue recording

USB converter

Video 8 analoguecamera

Audiovisual formats: MPEGAudiovisual formats: MPEG

Motion Pictures Expert Group (MPEG) has Motion Pictures Expert Group (MPEG) has developed several standards from which developed several standards from which some are highly used:some are highly used:

MPEG-1 (1988) – typical application: MPEG-1 (1988) – typical application: VideoCD (VCD)VideoCD (VCD)

MPEG-2 (1994) – typical application: DVD MPEG-2 (1994) – typical application: DVD video or Digital TVvideo or Digital TV

MPEG-4 – typical application: DivX or Xvid MPEG-4 – typical application: DivX or Xvid moviesmovies

Sound in MPEGSound in MPEG

The sound in an MPEG video can be stored in 3 The sound in an MPEG video can be stored in 3 possible layers. The layer no. 3 is known possible layers. The layer no. 3 is known separately as MP3 audio formatseparately as MP3 audio format

Other digital audio formats are: WAVE, WMA, Other digital audio formats are: WAVE, WMA, OGG, MP3pro, AAC, …OGG, MP3pro, AAC, …

The sound in the audio CD is uncompressed, The sound in the audio CD is uncompressed, while in the computer world the uncompressed while in the computer world the uncompressed sound – especially for archiving – is stored in the sound – especially for archiving – is stored in the WAVE format (*.wav)WAVE format (*.wav)

Most standalone players can also play MP3 Most standalone players can also play MP3 audio, while some of them can play also the audio, while some of them can play also the WMA or even AAC filesWMA or even AAC files

Bitrate in audio filesBitrate in audio files

bitrate in kbit/sbitrate in kbit/s audio CD: 1411 kbit/saudio CD: 1411 kbit/s MP3 CD quality: min. 128 kbit/sMP3 CD quality: min. 128 kbit/s Lower bitrate possible when our Lower bitrate possible when our

requirements are not so high and/or when requirements are not so high and/or when we may use WMA, AAC, or other formatswe may use WMA, AAC, or other formats

as the space needed for storage of digital as the space needed for storage of digital audio is not critical today, we should avoid audio is not critical today, we should avoid lower bitrateslower bitrates

MPEG-1 in VideoCDMPEG-1 in VideoCD

VCD is playable on standalone playersVCD is playable on standalone players VCD legal settings:VCD legal settings:

bitrate: 1140 kbit/sbitrate: 1140 kbit/s sound: 224 kbit/s in MPEG-1 layer 2sound: 224 kbit/s in MPEG-1 layer 2 still image resolution: 352x288 pixels in PAL, still image resolution: 352x288 pixels in PAL, 352x352x240240

in NTSCin NTSC 25 frames/s in PAL, 25 frames/s in PAL, 2323..976 frames/s976 frames/s in in NTSC NTSC

VideoCD is a product that has a firm structure. VideoCD is a product that has a firm structure.

One CD can contain ca. 70 minutes of VHS-like One CD can contain ca. 70 minutes of VHS-like video qualityvideo quality

MPEG-2 in DVD videoMPEG-2 in DVD video

DVD video that is playable on standalone DVD video that is playable on standalone playersplayers

Video DVD most typical legal settings:Video DVD most typical legal settings: bitrate: variable from 2.4 up to 9.6 mbit/sbitrate: variable from 2.4 up to 9.6 mbit/s sound: 192 kbit/s and more in MPEG layer 2 or PCM sound: 192 kbit/s and more in MPEG layer 2 or PCM

(uncompressed), AAC(uncompressed), AAC still image resolution: 720x576 pixels in PALstill image resolution: 720x576 pixels in PAL 25 frames/s in PAL25 frames/s in PAL

DVD video is a product that has a firm structure, DVD video is a product that has a firm structure, it consists if video objects (VOB). One DVD can it consists if video objects (VOB). One DVD can contain from ca. 60 minutes (high quality) to contain from ca. 60 minutes (high quality) to several hours of video (lower quality)several hours of video (lower quality)

MPEG-2 in SuperVideoCDMPEG-2 in SuperVideoCD

SVCD is playable on standalone playersSVCD is playable on standalone players SVCD legal settings:SVCD legal settings:

bitrate: max. 2600 kbit/sbitrate: max. 2600 kbit/s sound: 32 - 384 kbit/s in MPEG layer 2sound: 32 - 384 kbit/s in MPEG layer 2 still image resolution: 480x576 pixels in PAL, 480x480 still image resolution: 480x576 pixels in PAL, 480x480

NTSCNTSC 25 frames/s in PAL, 25 frames/s in PAL, 29,97 frames/29,97 frames/s in NTSCs in NTSC

SVCD is a product that has a firm structure. One SVCD is a product that has a firm structure. One SVCD can contain ca. 35 or more minutes of SVCD can contain ca. 35 or more minutes of videovideo

VCD – MPEG1

SVCD – MPEG2

DVD – MPEG2

Comparison of image resolution in typical optical disc video products

MPEG-4MPEG-4

Lower variable bitrate with comparably same quality as Lower variable bitrate with comparably same quality as in MPEG-2 (approx. 780 kbit/s gives good results)in MPEG-2 (approx. 780 kbit/s gives good results)

Can be combined with sound in various formats, but Can be combined with sound in various formats, but most typically MP3most typically MP3

Used mostly as DivX or Xvid approaches to encode Used mostly as DivX or Xvid approaches to encode MPEG-4, but possible also other ones, as e.g. MPEG-4, but possible also other ones, as e.g. NeroDigitalNeroDigital

The video and audio parameters can be various, but The video and audio parameters can be various, but some profiles are used the coimpatibility with standalone some profiles are used the coimpatibility with standalone devices, e.g. the Theatre Profile ensures the videos can devices, e.g. the Theatre Profile ensures the videos can be replayed on standalone DVD players (most of them be replayed on standalone DVD players (most of them can play also MPEG-4) can play also MPEG-4)

MPEG in computersMPEG in computers

*.mpg/mpeg – it does not say whether it is *.mpg/mpeg – it does not say whether it is MPEG 1 or 2MPEG 1 or 2

MPEG-4 is usually packed in *.avi; if it is made MPEG-4 is usually packed in *.avi; if it is made as NeroDigital then packed as *.mp4as NeroDigital then packed as *.mp4

AVI format (Audio-Video Interleave) can contain AVI format (Audio-Video Interleave) can contain a large variety of video and audio formats (it a large variety of video and audio formats (it must be always set up appropriately) or it can be must be always set up appropriately) or it can be uncompressed (very large files)uncompressed (very large files)

From other formats, most used is the Microsoft From other formats, most used is the Microsoft WMAWMA

What to use: softwareWhat to use: software Audiograbber (freeware at Audiograbber (freeware at

http://www.audiograbber.com-us.nethttp://www.audiograbber.com-us.net): it enables the ): it enables the Line-In recording of analogue soundLine-In recording of analogue sound

Video converters come usually with basic software, most Video converters come usually with basic software, most typically they convert into MPEG-2typically they convert into MPEG-2

DVD authoring: the low cost NERO Premium (DVD authoring: the low cost NERO Premium (http://www.nero.comhttp://www.nero.com) is a good solution) is a good solution

For MPEG-4, the Xvid (For MPEG-4, the Xvid (http://www.xvid.orghttp://www.xvid.org) authoring is ) authoring is based on freeware, while the for DivX (based on freeware, while the for DivX (http://http://www.divx.comwww.divx.com) encoding, the encoder must be ) encoding, the encoder must be purchasedpurchased

For work with Xvid (but not only), you may use the free For work with Xvid (but not only), you may use the free Auto Gordian Knot softwareAuto Gordian Knot software ((http://http://www.autogk.me.ukwww.autogk.me.uk))

What to use: formats and What to use: formats and parametersparameters

For audio use *.wav whenever possible and MP3 with For audio use *.wav whenever possible and MP3 with rich bitrates for applicationsrich bitrates for applications

For video convert into MPEG-2 with at least 4 mbit/s For video convert into MPEG-2 with at least 4 mbit/s variable bitrate (mostly enough for current VHS or variable bitrate (mostly enough for current VHS or Video8 quality) and 224 kbit/s MPEG Layer 2 soundVideo8 quality) and 224 kbit/s MPEG Layer 2 sound

Make all the other formats and/or products afterwards Make all the other formats and/or products afterwards (e.g. WMA or AVI Xvid video clips for Internet or VCD, (e.g. WMA or AVI Xvid video clips for Internet or VCD, SVCD, or DVD Video) from this master file that you SVCD, or DVD Video) from this master file that you should preserveshould preserve

Mind that for replay of special parameters you must have Mind that for replay of special parameters you must have special codecs (installed pieces of software that special codecs (installed pieces of software that decode/encode the files); therefore, avoid very special decode/encode the files); therefore, avoid very special untypical settingsuntypical settings

Further informationFurther information

MPEG website: MPEG website: http://www.chiariglione.org/mpeghttp://www.chiariglione.org/mpeg

Further information for those who are Further information for those who are about to start: about to start: http://www.videohelp.com/http://www.videohelp.com/