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--- tanszek:oktatas:techcomm:mpeg_compression [2024/11/19 11:03] – [Container Types for MPEG Compression] knehez
+++ tanszek:oktatas:techcomm:mpeg_compression [2024/11/19 11:06] (current) – [MPEG] knehez
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 ===== Principles of MPEG Compression =====
-The human ear perceives sound in the frequency range of 20 Hz to 20 kHz, with the most sensitive range being between 2-4 kHz (note: a tuning fork vibrates at a frequency of 440 Hz). A key characteristic of human hearing is that when two sounds of similar frequencies are played simultaneously, the one with higher intensity masks the one with lower intensity. This masking effect also occurs if the lower-intensity sound starts 2 ms earlier and ends approximately 15 ms later than the higher-intensity sound of a nearby frequency.
+**MPEG** compression offers various methods for both video and audio. In **MPEG**, it is crucial to keep audio and video synchronized over time, so audio and video data include timestamps.
-Quantization should be performed with particular attention to the fact that frequencies between 2-4 kHz require higher precision than those in the 10-20 kHz range.
-**MPEG** compression offers various methods for both video and audio. In video compression, MPEG takes into account changes between individual frames. It defines keyframes (I-frames) that compress the entire frame using the previously known JPEG method, while intermediate frames (P-frames, B-frames) contain information about changes. This is particularly important during fast-forward operations, as a full frame for a P-frame can only be reconstructed starting from the preceding I-frame since P-frames do not contain the complete image, only the changes.
-In **MPEG**, it is crucial to keep audio and video synchronized over time, so both audio and video include timestamps.
-==== Additional Information on MPEG Compression ====
 **MPEG** (Moving Picture Experts Group) compression is a widely used standard for reducing the file size of video and audio content while maintaining an acceptable level of quality. It achieves high compression ratios by eliminating redundant information spatially within a frame and temporally between consecutive frames.