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The disadvantages of transcoding are that there is quality loss when transcoding between lossy compression formats, and that the process is highly CPU-intensive. This article compares video converters that have their own articles on Wikipedia.
The quality the codec can achieve is heavily based on the compression format the codec uses. A codec is not a format, and there may be multiple codecs that implement the same compression specification – for example, MPEG-1 codecs typically do not achieve quality/size ratio comparable to codecs that implement the more modern H.264 specification.
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.
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.
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 —
Linear pulse-code modulation (LPCM, generally only described as PCM) is the format for uncompressed audio in media files and it is also the standard for CD-DA; note that in computers, LPCM is usually stored in container formats such as WAV, AIFF, or AU, or as raw audio format, although not technically necessary.