H.264 and HEVC are different video compression formats. A device or app must support the format actually used by the stream, including its relevant profile and bit depth. Supporting H.264 does not automatically provide HEVC decoding, even if both arrive in an MP4 container.
Separate compatibility from efficiency
HEVC was designed for more efficient compression than earlier H.264 implementations, but a particular stream’s quality still depends on its encoder and settings. There is no fixed saving that applies to every film or channel. A compatible, well-encoded H.264 feed may be the more practical choice on older hardware.
Read the media details
Look for AVC or H.264 and HEVC or H.265 in the player’s information panel. Note whether the problematic stream is 8-bit or 10-bit if that is shown. A codec name is more useful to support than the file extension, because the same container can carry several kinds of video.
Avoid codec-pack guesswork
On a television or streaming stick, installing unrelated packages is unlikely to add missing hardware capability. Use the player’s supported decoder choices and the device manufacturer’s documentation. If a browser cannot play a format, a supported native app may have a different media path, but that should be tested rather than assumed.
