Class VideoReader

CodenameOne/src/com/codename1/media/VideoReader.java:44–140

///
/// Obtain an instance from `VideoIO#openReader(String)`. Always `#close()` it when done.
public abstract class VideoReader {
    /// The width of the video track in pixels, or -1 if there is no video.
    public abstract int getWidth();

    /// The height of the video track in pixels, or -1 if there is no video.
    public abstract int getHeight();

    /// The total duration of the clip in milliseconds, or -1 if unknown.
    public abstract long getDurationMillis();

    /// The average/nominal frame rate of the source video track. For variable frame rate
    /// sources this is an average; use `#readFrames(float, FrameCallback)` to obtain an
    /// evenly spaced sequence.
    public abstract float getFrameRate();

    /// True if the clip has a decodable video track.
    public abstract boolean hasVideo();

    /// True if the clip has a decodable audio track.
    public abstract boolean hasAudio();

    /// The sample rate of the audio track in Hz, or -1 if there is no audio.
    public abstract int getAudioSampleRate();

    /// The number of channels in the audio track, or -1 if there is no audio.
    public abstract int getAudioChannels();

    /// Returns the frame at (or nearest at/before) the given timestamp, decoded to RGBA.
    /// Unlike seeking a `Media` player, the returned frame corresponds exactly to the
    /// requested position rather than the closest key frame.
    ///
    /// #### Parameters
    ///
    /// - `millis`: the timestamp to seek to in milliseconds
    ///
    /// #### Returns
    ///
    /// the decoded `VideoFrame`, or null if the position is past the end of the clip
    ///
    /// #### Throws
    ///
    /// - `IOException`: if decoding fails
    public abstract VideoFrame frameAt(long millis) throws IOException;

    /// Walks the entire clip, decoding and resampling it to the requested constant frame
    /// rate, invoking the callback once per output frame in increasing timestamp order.
    /// This converts a variable frame rate source to a constant frame rate sequence by
    /// duplicating or dropping source frames as needed.
    ///
    /// #### Parameters
    ///
    /// - `fps`: the target constant output frame rate in frames per second
    ///
    /// - `callback`: receives each decoded frame; return false from it to stop early
    ///
    /// #### Throws
    ///
    /// - `IOException`: if decoding fails