1 files changed, 140 insertions, 0 deletions
diff --git a/web/script/player/track/mse.ts b/web/script/player/track/mse.ts
new file mode 100644
index 0000000..623e149
--- /dev/null
+++ b/web/script/player/track/mse.ts
@@ -0,0 +1,140 @@
+import { JhlsTrackIndex, SourceTrack } from "../jhls.d.ts";
+import { OVar } from "../../jshelper/mod.ts";
+import { profile_to_partial_track, track_to_content_type } from "../mediacaps.ts";
+import { BufferRange, Player } from "../player.ts";
+import { EncodingProfileExt, ProfileSelector } from "../profiles.ts";
+import { PlayerTrack, AppendRange, TARGET_BUFFER_DURATION, MIN_BUFFER_DURATION } from "./mod.ts";
+
+export async function create_mse_track(player: Player, node_id: string, track_index: number, metadata: SourceTrack): Promise<MSEPlayerTrack | undefined> {
+  try {
+    const res = await fetch(`/n/${encodeURIComponent(player.node_id)}/stream?format=jhlsi&tracks=${track_index}`, { headers: { "Accept": "application/json" } });
+    if (!res.ok) return player.error.value = "Cannot download index.", undefined;
+    let index!: JhlsTrackIndex & { error: string; };
+    try { index = await res.json(); }
+    catch (_) { player.set_pers("Error: Failed to fetch node"); }
+    if (index.error) return player.set_pers("server error: " + index.error), undefined;
+
+    const t = new MSEPlayerTrack(player, node_id, track_index, metadata, index);
+    await t.init();
+    return t;
+  } catch (e) {
+    if (e instanceof TypeError) {
+      player.set_pers("Cannot download index: Network Error");
+    } else throw e;
+  }
+}
+
+export class MSEPlayerTrack extends PlayerTrack {
+  public source_buffer!: SourceBuffer;
+  private current_load?: AppendRange;
+  private loading = new Set<number>();
+  private append_queue: AppendRange[] = [];
+  public profile_selector: ProfileSelector;
+  public profile = new OVar<EncodingProfileExt | undefined>(undefined);
+
+  constructor(
+    private player: Player,
+    private node_id: string,
+    track_index: number,
+    private metadata: SourceTrack,
+    public index: JhlsTrackIndex
+  ) {
+    super(track_index);
+    this.profile_selector = new ProfileSelector(player, this, player.downloader.bandwidth);
+  }
+  async init() {
+    await this.profile_selector.select_optimal_profile(this.track_index, this.profile);
+    const ct = track_to_content_type(this.track_from_profile())!;
+    console.log(`track ${this.track_index} source buffer content-type: ${ct}`);
+    this.source_buffer = this.player.media_source.addSourceBuffer(ct);
+    this.abort.signal.addEventListener("abort", () => {
+      console.log(`destroy source buffer for track ${this.track_index}`);
+      this.player.media_source.removeSourceBuffer(this.source_buffer);
+    });
+    this.source_buffer.mode = "segments";
+    this.source_buffer.addEventListener("updateend", () => {
+      if (this.abort.signal.aborted) return;
+      if (this.current_load) {
+        this.current_load.cb();
+        this.loading.delete(this.current_load.index);
+        this.current_load = undefined;
+      }
+      this.update_buf_ranges();
+      this.tick_append();
+    });
+    this.source_buffer.addEventListener("error", e => {
+      console.error("sourcebuffer error", e);
+    });
+    this.source_buffer.addEventListener("abort", e => {
+      console.error("sourcebuffer abort", e);
+    });
+  }
+  track_from_profile(): SourceTrack {
+    if (this.profile.value) return profile_to_partial_track(this.profile.value);
+    else return this.metadata;
+  }
+
+  update_buf_ranges() {
+    const ranges: BufferRange[] = [];
+    for (let i = 0; i < this.source_buffer.buffered.length; i++) {
+      ranges.push({
+        start: this.source_buffer.buffered.start(i),
+        end: this.source_buffer.buffered.end(i),
+        status: "buffered"
+      });
+    }
+    for (const r of this.loading) {
+      ranges.push({ ...this.index.segments[r], status: "loading" });
+    }
+    this.buffered.value = ranges;
+  }
+
+  async update(target: number) {
+    this.update_buf_ranges(); // TODO required?
+
+    const blocking = [];
+    for (let i = 0; i < this.index.segments.length; i++) {
+      const seg = this.index.segments[i];
+      if (seg.end < target) continue;
+      if (seg.start >= target + TARGET_BUFFER_DURATION) break;
+      if (!this.check_buf_collision(seg.start, seg.end)) continue;
+      if (seg.start <= target + MIN_BUFFER_DURATION)
+        blocking.push(this.load(i));
+
+      else
+        this.load(i);
+    }
+    await Promise.all(blocking);
+  }
+  check_buf_collision(start: number, end: number) {
+    const EPSILON = 0.01;
+    for (const r of this.buffered.value)
+      if (r.end - EPSILON > start && r.start < end - EPSILON)
+        return false;
+    return true;
+  }
+
+  async load(index: number) {
+    this.loading.add(index);
+    await this.profile_selector.select_optimal_profile(this.track_index, this.profile);
+    const url = `/n/${encodeURIComponent(this.node_id)}/stream?format=snippet&webm=true&tracks=${this.track_index}&index=${index}${this.profile.value ? `&profile=${this.profile.value.id}` : ""}`;
+    const buf = await this.player.downloader.download(url);
+    await new Promise<void>(cb => {
+      if (this.abort.signal.aborted) return;
+      this.append_queue.push({ buf, ...this.index.segments[index], index, cb });
+      this.tick_append();
+    });
+  }
+  tick_append() {
+    if (this.source_buffer.updating) return;
+    if (this.append_queue.length) {
+      const seg = this.append_queue[0];
+      this.append_queue.splice(0, 1);
+      this.current_load = seg;
+      // TODO why is appending so unreliable?! sometimes it does not add it
+      this.source_buffer.changeType(track_to_content_type(this.track_from_profile())!);
+      this.source_buffer.timestampOffset = seg.start;
+      this.source_buffer.appendBuffer(seg.buf);
+    }
+  }
+}