video — u_pbt_video #

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Video player: a file of the workstation — streamed by the DLL, a long film starts at once — or a URL, with the component's own transport bar, which follows the theme: play, seek, time, mute, volume. WebVTT subtitles, a poster before playback, loop, speed, framing, capture of the current picture as PNG. Whatever the user does on the bar, your application knows.

▶ See it live — Demo application, Video player tile: the film, the code driving it and this page, side by side (Internet connection needed for the sample film).

At a glance #

Quick start #

// A film of the workstation, streamed by the DLL : starts at once
uo_video.is_poster = "img\packimages.dll:PNG/COVER"   // shown until the film starts
uo_video.is_subtitles = "films\training.vtt"
uo_video.of_play("films\training.mp4")

// A URL plays the same way
uo_video.of_play("https://www.w3schools.com/html/mov_bbb.mp4")

// The user pauses from the bar, or your code does : either way ue_paused fires
uo_video.of_pause()
uo_video.of_seek(90000)          // to 1:30, in milliseconds

Everything you set is a property (is_source, ii_volume, ib_loop…), read live from the component; everything you do is a method (of_play, of_pause, of_stop, of_seek, of_capture); everything that happens is an event (ue_started, ue_ended, ue_progress…). A missing file is not an exception: ue_failed says so, and the message shows on the picture.

Properties #

A click on the picture pauses, a second one resumes. Keyboard, when the film has the focus: Space or K play/pause, ←/→ five seconds, ↑/↓ volume, M mute, Home/End.

Methods #

Events #

Full screen, markers, segment, frame by frame #

• Full screen. of_fullscreen(true), a double click on the picture or the bar's last button. The DLL moves the control into a window of its own covering the monitor; your PowerBuilder window is not touched, and Escape brings the film back. ue_fullscreen_changed says it both ways.
• Markers. of_add_marker(ms, label) puts a tick on the bar: the user sees it, hovers it (the label), clicks it (the film jumps there, ue_seeked), and ue_marker_reached arrives when the film passes it. Chapters of a training, points to check, defects found.
• Segment. of_play_range(from, to) plays one extract only; with ib_loop it replays it until of_clear_range.
• Frame by frame. of_step_frames(±n) moves by n pictures at ii_fps a second and pauses; the keys . and , do the same. The engine does not say a film's rate: you do.
• The bar speaks. What only the user can do is reported by an event of its own: ue_seeked, ue_volume_changed, ue_rate_changed (the speed button, 0.5× to 2×), ue_subtitles_changed (the CC button). What your code does, it already knows: of_seek raises nothing.

// Chapters on the bar, then one extract in a loop
uo_video.of_add_marker(2000, "Intro")
uo_video.of_add_marker(5000, "The bunny")
uo_video.ib_loop = true
uo_video.of_play_range(2000, 8000)

// Surveillance : back one picture at a time
uo_video.ii_fps = 30
uo_video.of_step_frames(-1)

Playlist, subtitles, resuming, formats #

• Playlist. of_add_source piles up films; the first becomes is_source, the next ones follow by themselves at the end of each, ue_source_changed names every move. of_next and of_previous by hand.
• Several subtitle tracks. of_add_subtitles(language, file) per language; is_subtitle_lang picks, the bar's CC button cycles. A .srt is converted to WebVTT by the DLL when served: nothing to convert on your side.
• Resuming. ib_remember_position = true: where a film is left (pause, stop) is kept by the engine on this workstation, per user, and the next of_play of the same source resumes there. A film watched to its end starts over.
• Formats. What WebView2 decodes: mp4 (H.264, AAC), webm (VP8, VP9, AV1), ogv (Theora), and the audio formats (mp3, wav, ogg, flac, aac, m4a). No H.265/HEVC without the Windows extension, no old AVI, WMV, MKV, MOV: the component refuses them by name (ue_failed names the extension) rather than showing a black screen. No HLS nor DASH: an IP camera goes through an mp4 or webm stream.
• Several audio tracks. Chromium hides them behind a flag: not exposed.

// A playlist with two subtitle tracks, the position remembered
uo_video.ib_remember_position = true
uo_video.of_add_subtitles("en", "film.en.vtt")
uo_video.of_add_subtitles("fr", "film.fr.srt")     // .srt : converted by the DLL
uo_video.is_subtitle_lang = "fr"
uo_video.of_add_source("intro.mp4")
uo_video.of_add_source("lesson-1.mp4")
uo_video.of_play()

Examples #

A silent showcase loop, without a bar #

uo_video.ib_controls = false
uo_video.ib_muted = true
uo_video.ib_loop = true
uo_video.is_stretch = u_pbt_video.STRETCH_UNIFORMTOFILL
uo_video.of_play("films\showcase.mp4")

Your own buttons and a progress bar #

// cb_play.clicked
if uo_video.of_is_paused() or not uo_video.of_is_playing() then uo_video.of_play() else uo_video.of_pause()

// uo_video.ue_progress : once a second, no timer needed
hpb_progress.Position = al_position_ms * 100 / Max(al_duration_ms, 1)

A thumbnail of the film for a report #

uo_video.of_play("films\training.mp4")
uo_video.of_pause()
uo_video.of_seek(15000)                 // the frame at 0:15
// of_capture waits for the picture itself (10 s at most) : no timer to write
if uo_video.of_capture("report\training.png") <> 0 then MessageBox("Capture", uo_video.of_get_last_error())

Good practice #

• A file of the workstation rather than a URL whenever you can: streamed by the DLL, it starts at once, seeks without reloading, and of_capture may read its pixels — which a film from another site refuses.
• Script ue_failed on any film whose path depends on data: it is your only net, and the message is already on screen.
• Set ib_autoplay only for a showcase loop: a film that starts by itself with sound surprises the user; elsewhere the poster and the play button are enough.
• ue_progress replaces a timer: once a second, position and length, only while playing.

Inherited from the common base #

These members exist on every visual component — they are not specific to this one. They are detailed once, in the transverse chapters; this table only says where to read them.

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