Struct HistogramExtractor 

pub struct HistogramExtractor { /* private fields */ }

Extracts per-channel color histograms at configurable frame intervals.

Decodes the input video via VideoDecoder with RGB24 output conversion so that histogram accumulation is a simple one-pass loop with no additional format dispatch. FFmpeg’s histogram filter is deliberately not used because it produces video output rather than structured data.

Examples

use ff_decode::HistogramExtractor;

let histograms = HistogramExtractor::new("video.mp4")
    .interval_frames(30)
    .run()?;

for h in &histograms {
    println!("Frame at {:?}: r[255]={}", h.timestamp, h.r[255]);
}

Implementations

impl HistogramExtractor

pub fn new(input: impl AsRef<Path>) -> Self

Creates a new extractor for the given video file.

The default sampling interval is every frame (interval_frames = 1). Call interval_frames to sample less frequently.

pub fn interval_frames(self, n: u32) -> Self

Sets the frame sampling interval.

A value of N means one histogram is computed per N decoded frames. For example, interval_frames(30) on a 30 fps video yields roughly one histogram per second.

Passing 0 causes run to return DecodeError::AnalysisFailed.

Default: 1 (every frame).

pub fn run(self) -> Result<Vec<FrameHistogram>, DecodeError>

Runs histogram extraction and returns one FrameHistogram per sampled frame.

Frames are decoded as RGB24 internally; all pixel format conversion is handled by FFmpeg’s software scaler.

Errors

• DecodeError::AnalysisFailed — interval_frames is 0, the input file is not found, or a decode error occurs.
• Any DecodeError propagated from VideoDecoder.