IES: HTML-recog dk11 Flashcards
1
Q
- An open, bitstream container file format for audio, video, and other multimedia content.
- Designed to provide for efficient streaming and manipulation of high quality digital multimedia: the Ogg container format can multiplex (communicates two or more signals over a common channel) a number of independent streams for audio, video, text, and metadata.
- Codec “vorbis”
A
OGG
2
Q
- Requires audio resources to be encoded twice for playback across all browsers
- For this purpose two source elements may be nested within an audio element : rather than specifying a single resource URL to a src attribute in the audio tag
- For each file format, the source element can then specify their resource URL to a src attribute and they’re MIME type to a type attribute ( the browser will only load the supported audio resource for playback)
A
Absence of a universal codec across all browsers
3
Q
- Embeds video content in a document, such as a movie clip or other video streams.
- The <video> tag contains one or more <source></source> tags with different video sources. The browser will choose the first source it supports.</video>
- The text between the <video> and </video> tags will only be displayed in browsers that do not support the <video> element.</video>
- Include an id attribute so as to be referenced.
A
<video>
</video>
4
Q
- Specifies that the audio output of an audio or video resource should be muted.
- A Boolean attribute.
A
muted
5
Q
- Specifies an image to be shown while the video is downloading, or until the user hits the play button.
- If this is not included, the first frame of the video will be used instead.
A
poster
6
Q
- It is a good idea to always include width and height attributes: If height and width are not set, the page might flicker while the video loads.
A
Video display area
7
Q
- There are many video formats out there.
- The MP4, WebM, and Ogg formats are supported by HTML.(Only these three are supported by the HTML Standard)
- The MP4 format is recommended by YouTube.
A
Video compression standards
8
Q
- Advanced Video Coding-a patented standard that is also known as H.264 or MPEG-4 (.mp4 files)
- Video compression standard based on block-oriented, motion-compensated coding.
- It is by far the most commonly used format for the recording, compression, and distribution of video content, used by 91% of video industry developers as of September 2019.
- It supports resolutions up to and including 8K UHD.
A
AVC
9
Q
- An open, royalty free alternative to the patented H. 264 and MPEG-4 standard
- .webm files
- Designed for sharing video on the web.
- WebM uses a container structure similar to the Matroska (.MKV) video format, which stores both audio and video data.
- Video is compressed using a VP8 or VP9 codec, and audio is compressed with either the Vorbis or Opus audio codec.
- Several modern web browsers, such as Chrome, Edge, and Firefox, include built-in support for the WebM format.
A
WEBM
10
Q
- MP4
- WebM
- OGG
A
HTML video formats
11
Q
- Used as a child of the media elements, <audio> and <video></video></audio>
- Specifies timed text tracks (or time-based data): specifies subtitles, caption files or other files containing text, that should be visible when the media is playing.
- Tracks are formatted in WebVTT format (.vtt files).
- src attribute is required.
A
<track></track>
12
Q
- Web Video Text Tracks format’s main use is for marking up external text track resources in connection with the HTML <track></track> element.
- Provides captions or subtitles for video content, and also text video descriptions [MAUR], chapters for content navigation, and more generally any form of metadata that is time-aligned with audio or video content.
A
WebVTT
13
Q
- Begins with WEBVTT
- Start and end timing cues are added on new lines in the format - “HH:MM:SS.ss” and separated by ” -–> “
- The associated subtitle caption appears on a new line below each timing cue.
A
Subtitle files
14
Q
- Specifies the kind of text track
- Values: captions, chapters, descriptions, metadata, and subtitles
A
kind
15
Q
- Specifies the language of the track text data
- Required if kind=”subtitles”
A
srclang
