Post on 07-Sep-2015
description
Tehnici audio video
Mihai Onia
Evoluie?
Evoluie?
Recepie
Emisie
Transmisie video digital
Eantionare Cuantizare
Byte-bii Valori posibile1 byte (8 bii) 256 (28)2 bytes (16 bii) 65 535 (216)4 bytes (32 de bii) 232
8 bytes (64 de bii) 264
Transmisie video digital
Eantionare temporal i spaial a imaginii
Eantionarea i cuantizarea sunetului
Spaii de culoare
Standarde
SD TV - PAL
Rezoluii HD - SDDenumire Rezoluie Raport aspect
NTSC-M (SD) 720480 3:2
PAL-I (SD) 720x576 5:4
HD Ready 1280x720 16:9
full HD 1920x1080 16:9
4K 3840x2160 16:9
8K 76804320 16:9
Producie
Compacte: Point - and - Shoot
Bridge
DSLR (Digital Single Lens Reflex)
Producie
Achiziie - editare
Compresie i distribuie video
Formate audio-video
Format - container (wrapper) aduce impreuna mai multe tipuri de date (date audio -video, subtitrare, metadata)
Audio: WAV, AIFF, MP3 Video AVI, MOV, MP4, M4V,
MPG, VOB, FLV, WMV, MKV, RM, 3GP, WebM, M2TS, MXF
Codecuri
COder-DECoder - cu pierderi / fara pierderi Exemple de codecuri video: DV, MPEG4-H264,
MPEG2, VC-1, WMV9, VP6, DivX, XVID, MJPEG Audio: AAC, MP3, PCM SCOPUL CODECULUI
editare sau distributie?
Transcodare Transcodare conversia fisierelor video Softuri profesionale: Adobe Media Encoder,
GrassValley Procoder, Rhozet Carbon Coder Softuri gratuite: MediaCoder,
AnyVideo Converter, Super, VLCz
Parametrii de codare
Rata de bit (Bit Rate) VBR sau CBR
Rezoluia video (Video Frame Size)
Raport de aspect - imagine si pixel (Aspect Ratio)
Cadre pe secunda (fps) (video frame rate)
Adncimea de bit (Bith Depth)
Numr de canale audio (Audio Channels)
Rata de eantionare (Sampling Rate)
Broadcast TV (SD)
Container video: MPG, MP4Cadre pe secund: 25fpsRata de bit: 2-8 MbpsRezoluie: 720 x 576Raport de aspect: 16:9
IPTV(HD)
Container video: MP4Cadre pe secund: 25fpsRata de bit: 2-13 MbpsRezoluie: 1280 x 720, 1920 x 1080Raport de aspect:16:9
DVD
Container video: VOBCadre pe secund: 25fpsRata de bit: variabil 0 - 7 MbpsRezoluie: 720 x 576Raport de aspect: 4:3 sau 16:9
Blu-Ray
Container video: M2TS - MPEG Transport StreamCadre pe secund:
Web video - Youtube
Container video: FLV, MP4Cadre pe secund: 25-30fpsRata de bit: 0,3 - 1 MbpsRezoluie: 320 x 240, 480 x 360, 640 x 480, 1280 x 720, 1920 x 1080
Raport de aspect: 4:3 sau 16:9
iPhone
Container video: MP4Cadre pe secund: 25fpsRata de bit: ~1 MbpsRezoluie: max 1136 x 640