Which of the following file formats is NOT lossless?

MP4 is identified as a format that is not lossless because it typically uses lossy compression for audio and video data. In this compression method, some data is discarded to reduce the file size, which can affect the quality of the media. This is particularly important in streaming and playback scenarios where bandwidth considerations come into play, as smaller file sizes lead to quicker downloads and less buffering.

In contrast, TIFF and PNG are both lossless formats, meaning they compress images without losing any original data. This is beneficial for tasks that require high fidelity and quality, such as professional photography and graphic design. JPEG, while also a common image format, uses lossy compression, which leads to a reduction in image quality based on the level of compression applied. Thus, while JPEG might seem like a potential candidate for being not lossless, it is the MP4 format that definitively fits this classification.