Thumbnails: a VOD still recording asks Media for no job (it fails on a file still being written: a 500 every 5 minutes for VOD 5833); a quiet empty answer until the recording finalizes (#249)

ddiff --git a/server/media-proxy/thumbnails.js b/server/media-proxy/thumbnails.js
iindex 8aaa0d1f..14a400e9 100644
---- a/server/media-proxy/thumbnails.js
++++ b/server/media-proxy/thumbnails.js
@@@ -88,6 +88,12 @@ async function generateFor(kind, id, req, res) {
          if (!canManage && !isPublic) return res.status(403).json({ error: `Not your ${kind}` });
          const key = `${kind}:${Number(id)}`;
          if (noPictureKnown(key)) return res.json({ thumbnail_url: null });
++        // A recording still being written has no finished file to draw from: Media's job fails (a 500 every 5 minutes
++        // for VOD 5833 while it recorded, 2026-10-18). No picture yet; Media makes one when the recording finalizes.
++        if (kind === 'vod' && (meta.is_recording || meta.status === 'recording')) {
++            rememberNoPicture(key, MEDIA_BUSY_MS);
++            return res.json({ thumbnail_url: null });
++        }
          let out;
          try { out = await media.generateThumbnail(kind, id); } catch (err) {
              // Media's job failing (5xx) is Media's to fix, not this visitor's error: no picture for now, asked
ddiff --git a/test/thumbnail-no-picture.test.js b/test/thumbnail-no-picture.test.js
iindex d0bd47bf..eef4dec3 100644
---- a/test/thumbnail-no-picture.test.js
++++ b/test/thumbnail-no-picture.test.js
@@@ -71,6 +71,13 @@ console.warn = () => {};
      assert.strictEqual(asked, 5, 'another 404: asked again after an hour');
      Date.now = realNow;
  
++    // A VOD still recording: no Media job (it fails on a file still being written), a quiet empty answer.
++    media.getVod = async (id) => ({ id: Number(id), user_id: 1, visibility: 'public', thumbnail_url: null, is_recording: 1 });
++    let jobs = 0;
++    media.generateThumbnail = async () => { jobs++; return {}; };
++    const live = await post('/api/thumbnails/generate/vod/5833');
++    assert.deepStrictEqual([live.status, live.json, jobs], [200, { thumbnail_url: null }, 0], 'a recording VOD asks Media for nothing');
++
      server.close();
      console.log('thumbnail no-picture: all checks passed');
      process.exit(0);