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Most lossless compression programs do two things in sequence: the first step generates a statistical model for the input data, and the second step uses this model to map input data to bit sequences in such a way that "probable" (i.e. frequently encountered) data will produce shorter output than "improbable" data.
As such, the user normally does not have a H.264 file, but instead has a video file, which is an MP4 container of H.264-encoded video, normally alongside AAC-encoded audio. Multimedia container formats can contain one of several different video coding formats; for example, the MP4 container format can contain video coding formats such as MPEG-2 ...
The acceptable trade-off between loss of audio quality and transmission or storage size depends upon the application. For example, one 640 MB compact disc (CD) holds approximately one hour of uncompressed high fidelity music, less than 2 hours of music compressed losslessly, or 7 hours of music compressed in the MP3 format at a medium bit rate .
No No No No No No No TextST [viii] Text stream 2006-03 Patent encumbered Beta: No No No No No No No MicroDVD: Plain text: 2000-03 Proprietary: No No No No Needs alterations No No No Other Other — Varies Generic bitmap images, generic plain text [53] BIFS: Quicktime SMIL, EIA-608, CTA-708 — XSUB [x] SMPTE-TT, EBU-TT [108] [123] CTA-708 —
On the other hand, for spatial and quality bitstream scalability (i.e. the presence of a sub-bitstream with lower spatial resolution/quality than the main bitstream), the NAL (Network Abstraction Layer) is removed from the bitstream when deriving the sub-bitstream. In this case, inter-layer prediction (i.e., the prediction of the higher spatial ...
Video can be compressed immensely (e.g., 100:1) with little visible quality loss Audio can often be compressed at 10:1 with almost imperceptible loss of quality Still images are often lossily compressed at 10:1, as with audio, but the quality loss is more noticeable, especially on closer inspection.
In contrast to that, some very general-purpose container types like AVI (.avi) and QuickTime (.mov) can contain video and audio in almost any format, and have file extensions named after the container type, making it very hard for the end user to use the file extension to derive which codec or program to use to play the files.
A network packet is the basic unit of data in a transport stream, and a transport stream is merely a sequence of packets. Each packet starts with a sync byte and a header, that may be followed with optional additional headers; the rest of the packet consists of payload.