Drop an audio or video file and the browser parses MediaInfo-grade technical details locally: container, duration, bit rate, resolution, video and audio codecs, colour information, subtitle tracks and more. Four views — grouped tree / text / XML / JSON — with one-click copy. Everything runs on your machine; the file is never uploaded.
Drop or click to select a media file
How to read audio/video parameters
1. Layers first: container is not the codec
Container / muxing layer / track / codec / raw signal — five layers, top to bottom
Container and codec are different things: an MP4 can carry H.264 or H.265, and the same AAC stream can be muxed into MP4, MKV or TS. Always ask "is this a container property or a codec property?"
2. Key video parameters
| Aspect | Common values | Why it matters |
|---|---|---|
| Codec | H.264/AVC, H.265/HEVC, AV1, VP9, MPEG-2, ProRes | Compression, compatibility, hardware decode |
| Resolution | 1920×1080, 3840×2160; SAR / PAR / DAR | Pixels are not display size — watch rotation and DAR |
| Frame rate | 23.976 / 24 / 25 / 29.97 / 30 / 50 / 60, CFR vs VFR | Timebase decides timestamp precision |
| Bit depth | 8 / 10 / 12 bit | 10-bit is the basis of HDR and high quality |
| Chroma subsampling | 4:2:0 / 4:2:2 / 4:4:4 | 4:2:0 saves bits, 4:4:4 keeps chroma for post |
| Colour space | BT.601 / 709 / 2020; primaries · transfer · matrix | Missing any of the three shifts colours |
| HDR | HLG, PQ / HDR10, HDR10+, Dolby Vision | Needs depth + transfer function + metadata |
| Scan type | Progressive, Interlaced (TFF / BFF) | Deinterlace correctly or you get combing |
| Profile / Level | High@4.1, Main10@5.1 | Level caps resolution, frame rate and bit rate |
| GOP structure | I / P / B frames, keyint, IDR, closed vs open GOP | Affects seeking and live latency |
| Bitrate control | CBR / VBR / CRF / ABR; maxrate · bufsize (VBV) | CRF targets quality, VBV tames network jitter |
| Quality metrics | PSNR / SSIM / VMAF | VMAF tracks perception best; PSNR is only a number |
| Bitstream format | Annex-B start codes vs AVCC / HVCC length prefix | MP4 needs AVCC-formatted streams |
3. Key audio parameters
| Aspect | Common values | Why it matters |
|---|---|---|
| Codec | AAC-LC, HE-AAC, Opus, MP3, FLAC, ALAC, AC-3, DTS | Lossy for delivery, lossless for archival |
| Sample rate | 8k / 16k / 44.1k / 48k / 96k / 192k Hz | Video usually 48k; music often 44.1k |
| Bit depth | 16 / 24 / 32 bit, int vs float | Produce at 24-bit, deliver at 16-bit |
| Channels & layout | mono, stereo, 5.1, 7.1; L R C LFE Ls Rs | A wrong layout sends dialogue to the rears |
| Bit rate | 64–320 kbps; roughly 64k per channel minimum | VBR saves bits; CBR suits streaming |
| AAC profile | LC / HE / HEv2 / ELD; ADTS vs raw (LATM) | MP4 carries raw AAC; bare files use ADTS |
| Frame length | AAC 1024 (960) samples; Opus 2.5–60 ms | Drives latency and muxing alignment |
| Sample format | S16 / S24 / S32 / F32; planar vs interleaved | Planar for processing, interleaved for output |
| Loudness | LUFS (EBU R128), True Peak | Streaming targets around -14 LUFS, -1 dBTP |
| Lip sync | A/V offset, delay, timestamp drift | Sync issues are usually timestamps or delay |
| Subtitles | SRT / ASS / WebVTT / PGS; default vs forced | Forced shows only foreign-language parts |
4. GOP and I / P / B frames: why decode order differs from display order
I decodes standalone · P references earlier frames · B references both ways, so decode order differs from display order
A B frame needs the frame that comes after it, so that later P frame must be decoded first. That is the only reason containers carry two timestamps: PTS (when to show) and DTS (when to decode).
5. Suggested reading order for a report
- Container + codec combo — is it supported by the target device or browser?
- Resolution + frame rate + scan type — progressive or interlaced
- Bit depth + chroma subsampling + the three colour tags — colour shift and HDR eligibility
- Profile@Level — the ceiling for hardware decoding
- Video + audio bit rate — only meaningful next to resolution (bpp)
- Audio: codec + sample rate + channel layout — a wrong layout moves voices to the rear
- GOP / keyframe interval — seeking, precision and live latency
- Duration + size + per-track language / default / forced
Three classic traps: ① "MP4 won't play" is often
moov at the end of the file (no faststart), or an Annex-B stream that was never converted to AVCC; ② washed-out or over-saturated picture: primaries / transfer / matrix missing or mismatched, typically BT.601 mixed with BT.709; ③ A/V drift or wrong channels: usually container timestamps or track delay, not a broken encode.