This also explains why you achieved smaller file size with the High profile - obviously, you somehow set a constant quality level and the encoder could use more advanced compression techniques to create a video file that has the same quality as the Baseline profile, but with smaller size. Thus, if you give the encoder a certain bit rate to spend, it'll be able to create a better quality video with CABAC than with CAVLC because it achieves much better compression. It is also computationally more intensive. Some features of higher profiles may enable you to get the same quality with lower file sizes as compared to lower profiles.įor example, CABAC entropy coding ( Main and High) is more efficient than CAVLC ( Baseline). The profile only indirectly influences the quality. They can be used to save on bandwidth, but are harder to decode, which is why some devices might not support them. The primary profile for broadcast and disc storage applications, particularly for high-definition television applications (for example, this is the profile adopted by the Blu-ray Disc storage format and the DVB HDTV broadcast service).ī slices are for example only allowed in the Main profile and above. Especially the high profile is often used in broadcasting: It corresponds to the subset of features that are in common between the Baseline, Main, and High Profiles Primarily for low-cost applications, this profile is most typically used in videoconferencing and mobile applications. This has changed a little bit in the last years, where more and more phones can actually play main profile video, but not high profile. Android and iOS phones, for example, used to only be able to play video encoded with the baseline profile. Videos encoded with baseline profile can be easily played back, even on devices with lower computational power, such as old smartphones. Generally, the Baseline profile restricts the encoder to certain basic features only. What do the different profiles do?įor a detailed list, see H.264 Profiles on Wikipedia. With profiles, the encoder and decoder agree on a feature set that they can both handle. Profiles ensure compatibility between devices that have different decoding capabilities. Which ones it's allowed to enable is defined by the profile. A H.264 profile more or less defines what "bells and whistles" the encoder can use when compressing your video – and there are lots of H.264 features that the encoder can enable.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |