Audio and or video data is structurally and persistently associated with auxiliary sensor data (e.g., relating to acceleration, orientation or tilt) through use of a unitary data object, such as a modified MPEG file or data stream. In this form, different rendering devices can employ co-conveyed sensor data to alter the audio or video content. Such use of the sensor data may be personalized to different users, e.g., through preference data. For example, accelerometer data can be associated with video data, allowing some users to view a shake-stabilized version of a video, and other users to view the video with such motion artifacts undisturbed. In like fashion, camera parameters, such as focal plane distance, can be co-conveyed with audio/video content—allowing the volume to be diminished (or not, again depending on user preference) when a camera captures audio/video from a distant subject. Some arrangements employ multiple image sensors and/or multiple audio sensors—each also collecting auxiliary data. A great number of other features and arrangements are also detailed.