- #Mainconcept mpeg 4 video decoder download software#
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Third, quality depends on prefiltrations, which are included on all present-day codecs. Second, some codecs differentiate between different types of frames, such as key frames and non-key frames, differing in their importance to overall visual quality and the extent to which they can be compressed. A difference between variable bitrate (VBR) and constant bitrate (CBR) creates a trade-off between a consistent quality over all frames, on the one hand, and a more constant bitrate, which is required for some applications, on the other. First, all codecs have a bitrate control mechanism that is responsible for determining the bitrate and quality on a per-frame basis. Numerous factors play a role in this variability. Prior to comparing codec video-quality, it is important to understand that every codec can give a varying degree of quality for a given set of frames within a video sequence.
Each encoder implements the specification according to its own algorithms and parameters, which means that the compressed output of different codecs will vary, resulting in variations in quality and efficiency between them. The decoder component of a codec that also conforms to the specification recognises each of the mechanisms used, and thus interprets the compressed stream to render it back into raw video for display (although this will not be identical to the raw video input unless the compression was lossless). So long as the encoder component of the codec adheres to the specification it can choose any combination of these methods to apply different parts of the content. But quality/size ratio of output produced by different implementations of the same specification can also vary.Įach compression specification defines various mechanisms by which raw video (in essence, a sequence of full-resolution uncompressed digital images) can be reduced in size, from simple bit compression (like Lempel-Ziv-Welch) to psycho-visual and motion summarization, and how the output is stored as a bit stream. 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. The quality the codec can achieve is heavily based on the compression format the codec uses.
#Mainconcept mpeg 4 video decoder download license#
#Mainconcept mpeg 4 video decoder download software#
General software characteristics – for example:.Performance characteristics such as compression/decompression speed, supported profiles/options, supported resolutions, supported rate control strategies, etc.Video quality comparisons can be subjective or objective. Commonly video quality is considered the main characteristic of codec comparisons. Video quality per bitrate (or range of bitrates).For information about the GUIDs that represent media subtypes, see Video Subtype GUIDs.The following characteristics are compared in video codecs comparisons: The GUIDs for non-RGB media subtypes are the same, regardless of whether a decoder is acting as a DMO or an MFT. The globally unique identifiers (GUIDs) for RGB media subtypes differ depending on whether a decoder is acting as a DMO or an MFT. If you obtain an IMFTransform interface on the MPEG-4 V3 decoder, it behaves as an MFT. The MPEG-4 V3 decoder always behaves as a DMO.īy default, the MPEG-4 V3 decoder behaves as a DMO.
The following table shows the conditions under which an MPEG-4 V3 decoder behaves as a DMO or an MFT.
#Mainconcept mpeg 4 video decoder download windows#
The MPEG-4 V3 decoder behaves as a DMO or an MFT depending on which interfaces you obtain and which version of Windows is running. The object has the same class identifier (CLSID) regardless of whether it acts as a DMO or an MFT. The Windows Media MPEG-4 V3 decoder object exposes the IMediaObject interface so that the object can be used as a DirectX Media Object (DMO), and it exposes the IMFTransform interface so that the object can be used as a Media Foundation Transform (MFT). The Windows Media MPEG-4 V3 decoder supports the following output media subtypes when it is acting as a Media Foundation Transform (MFT). The Windows Media MPEG-4 V3 decoder supports the following output media subtypes when it is acting as a DirectX Media Object (DMO). The Windows Media MPEG-4 V3 decoder supports the following input media types. You can create an instance of the MPEG-4 V3 decoder by calling CoCreateInstance. The class identifier (CLSID) for the Windows MPEG-4 V3 decoder is represented by the constant CLSID_CMpeg43DecMediaObject. The Windows Media MPEG-4 V3 decoder decodes MPEG-4 V3 video streams.