Streaming quality glossary: resolution, bitrate, codecs, remux and HDR

Resolution

• 720p: commonly 1280 × 720 pixels.
• 1080p / Full HD: commonly 1920 × 1080 pixels.
• 2160p / UHD: commonly 3840 × 2160 pixels, often marketed as 4K. Cinema 4K uses different dimensions.

More pixels can preserve more detail, but an upscale or heavily compressed UHD file can look worse than a good 1080p version. Viewing distance and screen size also matter.

Bitrate

Bitrate is the amount of data per second, commonly expressed as Mbps for video. With comparable encoding conditions, more bitrate can preserve more detail. Comparisons across different codecs, encoders and source material are less reliable. A larger file is not automatically better: duration, audio tracks and encoding efficiency also affect file size.

Smooth streaming requires enough sustained bandwidth for the stream, including bitrate peaks and network overhead. There is no universal bitrate that guarantees good 4K video.

Codecs and containers

• H.264 / AVC: a widely supported video codec, subject to device profile and level limits.
• H.265 / HEVC: can provide greater compression efficiency than H.264, with support depending on hardware and software.
• AV1: a video codec designed for efficient compression. Hardware decoding is not available on every recent device.
• MP4 / MKV: container formats that hold video, audio, subtitles and metadata. A supported container does not guarantee support for every codec inside it.

Check the actual codec, bit depth, profile, resolution and audio format against your device. See MDN's video codec guide.

Remux

Remuxing moves existing encoded streams into another container without re-encoding those streams. It is not limited to disc sources and does not improve the original picture. The term does not establish whether a copy was made or distributed with permission. This glossary does not recommend obtaining disc or streaming-service copies.

HDR and SDR

• SDR: standard dynamic range. Properly mastered SDR can look excellent.
• HDR10: an HDR format that uses static metadata.
• HDR10+: an HDR format with dynamic metadata.
• Dolby Vision: a family of HDR profiles with dynamic metadata; compatibility varies by profile, container and playback chain.

HDR is not a guarantee of a wider color gamut, better grading or a brighter-looking picture in every scene. Benefits depend on the master, display and playback chain. Do not assume every Dolby Vision file has an HDR10 fallback: some profiles do not. An unsupported file may display incorrectly or fail to play.

Audio

AAC, Dolby Digital and Dolby Digital Plus are audio codecs. Dolby TrueHD and DTS-HD Master Audio can carry lossless audio. Dolby Atmos and DTS:X support immersive audio presentations; the result depends on the track, decoder and speaker system. Audio passthrough support depends on the player, device, connection and receiver.

What MIRA Player promises

MIRA supports 4K and HDR when your source, device and display support them. It cannot add missing detail, fix a poor encode or make every codec compatible. MIRA does not supply video files or content sources. Use only content you are authorized to access. See supported devices for current platform information.