* sfu: forward the dependency descriptor for VP8 simulcast
libwebrtc sends VP8 with a one byte payload descriptor when it sends the
dependency descriptor, so a VP8 subscriber gets neither picture IDs nor the
descriptor and finds frame references by sequence number alone. Under loss
with temporal filtering it stalls until a key frame.
DDForwarder rewrites the publisher's descriptor for each forwarded packet:
frame numbers continue across simulcast layer switches and stream restarts,
the structure goes out with the current layer's key frame, and the active
decode targets follow the forwarded temporal layer.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* sfu: keep VP8 descriptor frame numbers from going back
Rebase frame numbers only when a new stream would go back past the last
number sent: on a layer switch, a stream restart (also when it starts with a
delta frame) and a new forwarder on the same downtrack, which now carries
over the last number sent.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* sfu: set VP8 descriptor decode targets from the packet's layer
The active decode targets use the temporal layer the packet is forwarded at,
not the selector's next layer on the last packet before a down switch. They
also go out on key frames, combined with the publisher's own mask.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* sfu: carry the current active decode targets on every DD packet
The parser puts the stream's current mask on every packet, so a mask change
on a dropped packet still reaches the VP8 descriptor forwarder, which no
longer tracks the publisher's mask itself.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* sfu: take the first DD active decode targets mask at any sequence number
A publisher whose first packet has RTP sequence number 0 never had its key
frame's mask applied, so every packet reported no active decode targets.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
* sfu: parse VP8 and VP9 payload descriptors without an allocation
Replace ExtPacket.Payload with typed VP8 and VP9 pointer fields that point
at backing structs inside the ExtPacket, so parsing does not allocate and a
wrong codec type is a compile error.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* sfu: copy the VP8 descriptor in the test packet helper
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
* sfu/buffer: parse the dependency descriptor without allocating
Every VP9 and AV1 SVC packet allocated six objects in the dependency
descriptor parse: the descriptor, a clone of the frame template with
its three slices, a resolution copy, and a frame entity that took the
address of a parameter.
The pooled ExtDependencyDescriptor now owns the storage for the
descriptor, the template and the resolution, with fixed arrays for the
template's slices. The reader copies the matching template into that
storage.
Delta frame parse: 6 allocs, 176 B, 174 ns -> 0 allocs, 0 B, 122 ns.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
* sfu/dd: never copy a parsed frame into a structure template
A caller can hand Unmarshal a descriptor whose FrameDependencies points
at one of the structure's templates. Copying the packet's custom fields
into it would change the template for every later packet, so the reader
allocates a fresh template in that case.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---------
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
* sfu/buffer: stop allocating per ingested packet
Buffer.Write allocated six objects for every RTP packet. They were
the parsed rtp.Packet, a copy of it in patchExtPacket, and the flow
state, whose address two rare log calls took. The rest were an
AbsCaptureTime, present on about one packet per second, and the
extension slice that pion grows with append.
Unmarshal into a pooled scratch packet. Give ExtPacket its own backing
rtp.Packet and an [8]rtp.Extension array, and copy the header into
them. Patch the payload in place. If the abs-capture-time extension is
present, parse it. Log a copy of the flow state.
Per packet, Write plus ReadExtended. Opus: 6 allocs, 448 B -> 0.
VP8: 6 allocs, 416 B -> 1 alloc, 32 B. Opus 240 -> 142 ns, VP8 269 -> 204 ns.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
* sfu/buffer: point extension payloads at the bucket copy on read
Queued ExtPackets kept extension payload slices into the write input,
which the transport reuses for the next packet. ReadExtended now parses
the header again from the bucket copy, so extensions and CSRCs point
into RawPacket like the payload does.
The test writes every packet through one input buffer and checks the
audio level of each packet read back.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
* sfu/buffer: test that a dropped padding packet keeps the shifted sequence number on read
The bucket stores the shifted number, so re-parsing the header on read
returns it. This test guards that.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---------
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
pion no longer starts the repair stream reader when a custom BufferFactory
is set, so the mid/rid/rsid extensions were never observed and simulcast RTX
streams were never paired with their primary streams.
Extract the extensions on the buffer write path instead. Migrated publishers
send no extensions at all, so pair those from SimTracks.
Adds an integration test covering both paths, and moves the vnet setup it
shares with the downtrack test into pkg/testutils/vnettest.
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Flush the downtrack sequencer on stream restart (Resync, ReceiverRestart,
codec change) so NACK retransmissions can't use metadata that no longer
matches the resynced bucket. Add a defensive bounds guard on the RTX and
forward payload slicing.
Cap the PacketHistory and FrameIntegrityChecker catch-up loops to the ring
size so a large sequence/frame-number jump can't drive a big per-packet
iteration count.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
* Fix skipped packets accounting.
No need to copy unskipped packet RTP header to skipped packet.
That was causing padding bytes to be counted.
Also use Header.PaddingSize as base PaddingSize is deprecated.
* PaddingSize in header in utils
Reverting
- https://github.com/livekit/livekit/pull/4521
- https://github.com/livekit/livekit/pull/4525
There are TWCC feedback packets that are larger than MTU. Seems to
happen under a couple of conditions
1. Bad client data, i. e. severely out-of-order packets, bad sequence
numbers, etc.
2. On an ICE restart - this is rare, but it seemed to be flaky network
with some packets arriving and some not and causing a lot of gaps.
Either case, not much to do. If fargmentation/re-assembly back to
publisher works, the feedback will make it through. If not, feedbacks
will be missed and clients have to work with some missing data which is
not unexpected and the protocol is designed to handle.
However, filed pion/interceptor issue just in case - https://github.com/pion/interceptor/issues/416
Not a major issue, but just avoiding duplicate creation of NACK module.
RTCP feedback of `nack` and `nack pli` end up getting treated as `nack`
and was double creating.
* Log large packets receive/send.
Seeing cases of servers reporting need for segmentation/re-assembly of
packets. So, logging packet receive/send for RTP/RTCP to check if
anything is seeing more than 1400 byte packets.
* log downtrack RTCP too
David Chen