Every day, a large number of videos are uploaded to the video hosting websites such as Youtube and Vimeo where people can watch entire movies immediately. However if a video is shot in 4k RAW on a professional camera and is intended to be viewed on a website like Youtube, it would need to be scaled down since thirty minutes would amount to roughly 63 Gigabytes of content. It needs to be compressed down to the allowable resolution. The goal is to minimize loss in picture quality while still keeping the file size manageable. This process of reformatting the content to be streamed on Youtube is called transcoding. So by transcoding one digital encoding is converted to another and it is needed when a particular target device does not support the format or does not have enough storage capacity to support the file size or sufferes not enough powerful CPU. The codec used for compression in video is typically H.264, a standard for providing high definition video at substantially lower bit rates. The x264 Library is used for encoding H.264/MPEG-4 AVC, undergirds some of the most high profile streaming operations on the web, including YouTube, Vimeo and Hulu. When compiled with FFmpeg tool, it is capable to produce high quality compression at relatively high speeds. FFmpeg has been an important encoding tool for more than a decade. It is a powerful, multi-purpose open-source library with a wide range of command lines, which can be effectively utilized in conjuction with programming experience and high performance web servers to stream content to the web world. Given these introductions, the purpose of this thesis is to go through media based projects with essential need of transcoding and to study H.264 video codec and FFmpeg encodig tool.
Ogni giorno, un numero elevato di video sono caricati online su siti web di video hosting come Youtube e Vimeo dove le persone possono guardare film interi immediatamente. Tuttavia, se un video viene girato in 4k RAW su una videocamera pro- fessionale e si intende offrirne la visione su Youtube, sarebbe necessario scalarlo poich`e 30 minuti comporterebbero un costo di circa 63 Gigabytes di contenuto. Necessita di essere compresso fino ad una risoluzione ammissi- bile. L’obiettivo `e quello di minimizzare la perdita di qualit`a nell’immagine mantenendo le dimensioni del file gestibili. Questo processo di riformattare il contenuto che deve essere trasmesso su Youtube `e chiamato transcoding. Perci`o per mezzo del transcoding, una codifica digitale viene convertita in un’altra ed `e necessaria quando un particolare dispositivo target non supporta il formato o non ha capacit`a di memoria sufficiente per supportare la grandezza del file o non ha una CPU con potenza sufficiente. Il codec usato per la compressione in video `e tipicamente H.264, uno standard che fornisce video ad alta definizione a bit rate sostanzialmente pi` u bassi. La Libreria x264 `e usata per codificare H.264/MPEG-4 AVC, sottende alcune delle operazioni di streaming di maggior profilo sul web, inclusi Youtube, Vimeo a Hulu. Quando compilata con lo strumento FFmpeg, `e in grado di realizzare compressioni di alta qualit`a a velocit`a relativamente elevate. FFmpeg `e un importante strumento di encoding ` una potente libreria multi funzione open-source da pi` u di dieci anni. E con un’ampia gamma di comandi da terminale, che pu`o essere utilizzata efficacemente in combinazione all’utilizzo di altri programmi e a web server ad altre prestazioni per trasmettere contenuto sul web. Sulla base di queste promesse, lo scopo di questa tesi `e di presentare progetti basati sui media con la necessit`a essenziale di effettuare il transcoding e di studiare il codec video H.264 e lo strumento di codifica FFmpeg.
Transcoding h.264 video via FFMPEG encoder
HASHEMIZADEHNAEINI, SHABNAM
2014/2015
Abstract
Every day, a large number of videos are uploaded to the video hosting websites such as Youtube and Vimeo where people can watch entire movies immediately. However if a video is shot in 4k RAW on a professional camera and is intended to be viewed on a website like Youtube, it would need to be scaled down since thirty minutes would amount to roughly 63 Gigabytes of content. It needs to be compressed down to the allowable resolution. The goal is to minimize loss in picture quality while still keeping the file size manageable. This process of reformatting the content to be streamed on Youtube is called transcoding. So by transcoding one digital encoding is converted to another and it is needed when a particular target device does not support the format or does not have enough storage capacity to support the file size or sufferes not enough powerful CPU. The codec used for compression in video is typically H.264, a standard for providing high definition video at substantially lower bit rates. The x264 Library is used for encoding H.264/MPEG-4 AVC, undergirds some of the most high profile streaming operations on the web, including YouTube, Vimeo and Hulu. When compiled with FFmpeg tool, it is capable to produce high quality compression at relatively high speeds. FFmpeg has been an important encoding tool for more than a decade. It is a powerful, multi-purpose open-source library with a wide range of command lines, which can be effectively utilized in conjuction with programming experience and high performance web servers to stream content to the web world. Given these introductions, the purpose of this thesis is to go through media based projects with essential need of transcoding and to study H.264 video codec and FFmpeg encodig tool.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/120003