Pixeltable vs Supabase
Same video-intelligence app, two implementations. Pick Supabase when you want Postgres, row-level security, realtime, and a managed database. Pick Pixeltable when the pipeline is the product: video, frames, transcripts, embeddings, and retrieval in one Python file. They are not mutually exclusive.
pip install 'pixeltable[serve]'The trade
| Side | Pixeltable | Supabase |
|---|---|---|
| At a glance |
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What we measured
Same app. Pixeltable loses ingest, search, evolve wall-clock, RLS, and realtime. Pixeltable wins in-platform media and incremental schema.
| Feature | Pixeltable | Supabase |
|---|---|---|
| Total code for this app | 129 lines, 1 file | 546 lines (294 + 252 compute-service), 7 files |
| ffmpeg, Whisper, CLIP | Computed columns, same process | compute-service; three of seven endpoints have no hosted-API substitute |
| Processing for any writer | Yes — the pipeline is the schema | No, unless you add database triggers |
| Add a derived column (lines) | 1 line, 1 file, one command | 24 lines, 2 files: ALTER TABLE plus a backfill script |
| Add a derived column (wall time) | 3.88s (schema change and backfill are the same step) | 1.6s — fastest of the three at two dozen rows |
| Ingest, 20 videos / 10 min | 66.7s, 9.04× realtime | 51.8s, 11.64× realtime |
| Frame search p50 | 39.0ms | 26.1ms |
| Authenticated endpoints | Open in this repo | One line: withSupabase({ auth: 'secret' }) |
| Row-level security | None here | Enabled and verified on all five tables |
| Realtime push | None here | Built in |
| Per-cell errors and lineage | errormsg / errortype; pxt dashboard draws what produced a column | A failed step leaves NULL; Studio does not record lineage |
| Vendor checker in CI | ruff — generic Python; no Pixeltable conformance checker | deno lint and supabase db advisors on a live database |
All three beat realtime on this laptop
20 videos, 10 minutes of footage, CPU, local models — not Cloud. Bold is best on that row.
Ingest
| Feature | Pixeltable | Supabase |
|---|---|---|
| Wall time | 66.7s | 51.8s |
| Faster than realtime | 9.04x | 11.64x |
| First video | 5.3s | 4.1s |
| Median video | 3.1s | 2.1s |
Search
| Feature | Pixeltable | Supabase |
|---|---|---|
| Frame search p50 | 39.0ms | 26.1ms |
| Frame search p95 | 42.9ms | 30.5ms |
| Transcript search p50 | 18.5ms | 13.7ms |
| Transcript search p95 | 21.6ms | 16.3ms |
20 videos, 603.7 seconds of footage, 603 frames, 70 transcript chunks, one laptop, CPU, local models (Pixeltable 0.7.8). All three finished 20 of 20, all faster than realtime. Supabase led ingest (11.64× vs Pixeltable’s 9.04×); frame search is 26–39ms and most of that is embedding the query, not the index. 603 vectors is not a million-row benchmark, hosted Pixeltable Cloud was not in this run, and none of this is a cost comparison.
Adding a column to live data
One computed title-embedding index on a populated catalog. Lines compound; these seconds do not.
| Feature | Pixeltable | Supabase |
|---|---|---|
| Schema change | 3.88s | 0.07s |
| Backfill | same step | 1.52s |
| Total | 3.88s | 1.6s |
| Lines written | 1 | 24 |
| Files touched | 1 | 2 |
- Supabase is the fastest in wall time. At two dozen rows the backfill is noise; anyone quoting these seconds as a scaling result is quoting noise.
- After pxt schema update, an insert against the already-registered route answers 409 until pxt service update. Reads keep working. The other two resolve the table on every request.
- Backfill time is the part that scales, and this corpus cannot show it. Pixeltable’s backfill is work proportional to the rows that changed; a backfill script is work proportional to the table.
Ingest a video
Insert a video. Frames, audio, transcripts, embeddings, and scenes have to exist after that. On Pixeltable they are the schema. On the other two they live in the ingest path and in a second service.
Pixeltable
class Videos(TableModel, name='videos'):video: pxt.Videotitle: pxt.Stringaudio = extract_audio(video, format='mp3')duration_sec = pxtf.video.get_duration(video)scenes = video.scene_detect_content(threshold=8.0)class Frames(TableModel, name='frames', base=Videos,iterator=frame_iterator(Videos.video, fps=1.0)):still = pxtf.image.resize(frame, (320, 180))__indexes__ = [pxt.EmbeddingIndex(frame, embedding=VISUAL)]class Chunks(TableModel, name='chunks', base=Videos,iterator=audio_splitter(Videos.audio, duration=10.0)):transcript = transcribe(audio_segment, model='base.en').text.astype(pxt.String)__indexes__ = [pxt.EmbeddingIndex(transcript, embedding=SEMANTIC)]Videos.insert([{'video': 'lecture.mp4', 'title': 'CS101'}])
Supabase
const { frames } = await compute("/extract-frames", { video_url, fps: FRAME_FPS });const { embeddings } = await compute("/embed-clip", { images_b64: frames });const frameRows = await Promise.all(frames.map(async (b64, i) => {const path = `videos/${videoId}/frame_${i}.jpg`;await supabase.storage.from("frames").upload(path, decodeBase64(b64), {contentType: "image/jpeg", upsert: true,});return { video_id: videoId, frame_idx: i, embedding: embeddings[i] };}));await supabase.from("frames").insert(frameRows);
Search frames
Find frames of a whiteboard. Pixeltable asks the index. The other two embed the query themselves, then join or fetch rows in a second step.
Pixeltable
sim = Frames.frame.similarity(string=query)return (Frames.order_by(sim, asc=False).limit(limit).select(frame_url=Frames.still,frame_idx=Frames.pos,video_title=Frames.title,similarity=sim,))
Supabase
CREATE FUNCTION search_frames(query_embedding vector(512), match_count INT)RETURNS TABLE(frame_url TEXT, frame_idx INT, video_title TEXT, similarity FLOAT) AS $$SELECT f.frame_url, f.frame_idx, v.title,1 - (f.embedding OPERATOR(public.<=>) query_embedding)FROM public.frames fJOIN public.videos v ON f.video_id = v.idORDER BY f.embedding OPERATOR(public.<=>) query_embeddingLIMIT match_count;$$ LANGUAGE sql STABLE;
Add a column to live data
Make the video title semantically searchable. The rows already exist. An embedding is not derivable in SQL, so every existing row has to be read, sent to a model, and written back.
Pixeltable
class Videos(TableModel, name='videos'):...__indexes__ = [pxt.EmbeddingIndex(title, embedding=SEMANTIC)]# pxt schema update app.py media# updated media/videos# unchanged media/frames, media/chunks, media/conversations
Supabase
ALTER TABLE videos ADD COLUMN IF NOT EXISTS title_embedding vector(384);CREATE INDEX IF NOT EXISTS videos_title_embedding_idx ON videosUSING hnsw (title_embedding vector_cosine_ops);// then a script, because Postgres cannot call a model:const { data: rows } = await db.from("videos").select("id,title").is("title_embedding", null);for (let i = 0; i < rows.length; i += BATCH) {/* embed the batch, update each row */}
When to choose which platform
Choose Pixeltable when
- The pipeline is the product
Video, audio, images, documents, embeddings, and a retrieval step over them. The whole backend is one file, and nothing extra has to exist to run ffmpeg.
- Schema changes have to stay cheap
Adding a column backfills only that column. A row inserted by anything at all gets processed. That compounds; a line-count difference does not.
- You already have an app backend
Pixeltable as the media and retrieval layer behind a Supabase application is a coherent architecture, and for a team that already runs Postgres it is likely cheaper than moving.
Choose Supabase when
- You want Postgres and the things around it
Realtime subscriptions, row-level security for multi-tenancy, an auto-generated REST API, PITR, database branching, or a managed database your team already knows how to operate. Media work will live in a second service. That is the trade.
- Throughput at this scale is the binding constraint
On 20 videos and 10 minutes of footage, Supabase ingests fastest and answers frame search fastest. If that is the constraint, follow it rather than the sponsor.
Making the right choice
What this page does not measure
- Cost in dollars, multi-tenant authorization against auth.uid(), p99 latency, and on-call.
- Reproduce the numbers: https://github.com/pixeltable/pixeltable-vs-supabase-vs-convex
Frequently asked questions
One file. The whole pipeline.
Declare the tables. Apply the schema. Insert a row. Serve the same file.