FramePeek

Inspect the file, not the label.

FramePeek opens a video or audio file and measures what is actually in it. Bitrate over time, GOP structure, EBU R128 loudness, A/V drift and HLS ladders. Built on AVFoundation. No FFmpeg.

Download for macOS Source macOS 15.2+ · MIT
FramePeek showing a bitrate-over-time chart, a keyframe thumbnail strip and the GOP structure for Big Buck Bunny, with a metadata inspector on the right.
Overall
9 725 kb/s
Peak
30 242 kb/s
GOPs
597
Pattern
Irregular

Declared vs measured

The manifest is a claim. Check it.

Paste a playlist URL or open a local folder. FramePeek walks every variant, measures the segments and flags the ones whose real peak exceeds the BANDWIDTH they advertise. It also checks segment durations, keyframe alignment across the ladder, and whether CODECS matches what the segments actually contain.

Per-variant table for a five-rendition ladder listing resolution, codecs, declared bandwidth, measured bitrate, peak and segment count. Two rows show the peak in red. Findings list grouped into errors and warnings, including two measured peak segment bitrates that exceed the declared BANDWIDTH and two CODECS strings that do not match the segments.
A public test ladder. Two variants break the RFC 8216 rule that BANDWIDTH is an upper bound; two more declare a CODECS string their segments do not match.

Loudness

R128 without a render.

Integrated loudness, true peak and loudness range, gated per ITU-R BS.1770-4. The short-term curve is drawn against the -23 LUFS target, so you can see which passage is pulling the number.

Loudness card showing integrated -18.5 LUFS, true peak 0.6 dBTP and range 23.7 LU, above a short-term LUFS curve. A per-track audio waveform sits above it.
Integrated -18.5 LUFS · true peak 0.6 dBTP · range 23.7 LU. Both the integrated value and the true peak are flagged against R128.

A/V sync

Find the drift before QC does.

Audio and video timestamps compared track by track, with the frame interval distribution underneath. Constant frame rate, variable frame rate and duration mismatches all show up here.

Audio/Video sync card reporting an in-sync verdict, 0.0 ms offset, 40.7 ms duration delta, 24.000 FPS constant frame rate and 14 319 frames analysed.
0.0 ms offset across 14 319 frames · 24.000 FPS CFR · 40.7 ms duration delta between the audio and video tracks.

Headless

Same analyses, no window.

framepeek-cli runs every analysis from the shell as JSON, text or CSV, so it drops into a batch job or a CI step. The same tools are exposed over MCP, which lets an agent read a file's real properties instead of guessing at them. 

$ framepeek-cli big_buck_bunny_1080p_h264.mov --info --pretty

{
  "codec" : "H.264",
  "codecProfile" : "Main@L4.1",
  "resolution" : "1920x1080",
  "frameRate" : "24.000 FPS",
  "chromaSubsampling" : "4:2:0",
  "colorPrimaries" : "ITU_R_709_2",
  "overallBitrate" : "9725 kb/s",
  "durationFormatted" : "9m 56s"
}
$ framepeek-cli *.mp4 --all --parallel
$ framepeek-cli video.mp4 --bitrate --format csv
$ framepeek-cli video.mp4 --loudness --pretty

# expose the same analyses to an agent
$ claude mcp add framepeek -- framepeek-cli mcp

# tools: analyze_media, media_summary,
#        inspect_container, inspect_hls_ladder

Open a file and look.

Signed and notarised. The CLI ships as a separate tarball on the same release.

Download for macOS