Emil Lundmark 7f876c8930 Allow full SVC to reference T0 frame only after it has been encoded
The VP9 encoder may drop a frame internally which will not advance the
frame pattern. Consider the following scenario where only spatial layer
0 and temporal layer 0 is active:

1. Key frame encoded
2. Spatial layer 1 is activated
3. Delta T0 dropped
4. Delta T0 encoded

No S1T0 frame is encoded in (1) since it's not active. When
NextFrameConfig is called in (3) it will say that future frames may
reference T0 on both S0 and S1, but it's then dropped.

On step (4), the SVC controller essentially thinks it's encoding a new
picture and will happily reference the T0 on what it thinks is the first
delta frame. However, this is actually still the key frame and since
there was no S1T0 frame produced it will reference an invalid buffer.

To fix this, only say it's possible to reference a T0 frame after it has
been successfully encoded.

Bug: webrtc:11999, webrtc:13142, chromium:1178444
Change-Id: Iab3d2042ce0b3fa7d952b2831d1a36b1a6613a86
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231695
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Emil Lundmark <lndmrk@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34982}
2021-09-13 15:52:42 +00:00
..
2018-06-21 13:09:03 +00:00
2019-03-12 20:47:15 +00:00
2017-09-15 04:25:06 +00:00
2017-09-15 04:25:06 +00:00
2021-04-11 18:25:08 +00:00
2017-09-15 04:25:06 +00:00
2017-09-15 04:25:06 +00:00

This is a collection of corpora for various WebRTC fuzzers. To use
them, the gn targets define seed_corpus=$corpus_dir, which causes the
ClusterFuzz upload bot to bundle $corpus_dir and upload it.

The format is simple: one file per test case. Specific notes are
included below.

### SDP ###
This corpus was initially assembled manually from the following
sources:

  - curl --silent https://www.ietf.org/rfc/rfc4317.txt | grep '^[ a-z]*=[^=]*$' | sed 's/^[[:space:]]*//' | awk -v RS='(^|\n)v=' '/./ {print "v="$0 > NR".sdp"}'
  - all the SDPs used in the parser unit tests
  - some manually gathered SDPs from Firefox and Opera

The SDP tokens come from:

 -  grep "^static const " webrtc/api/webrtcsdp.cc | cut -d'=' -f2 | cut -d ';' -f1 | tr -d '"' | tr -d "'" | tr -d ' ' | sort -u | grep -v '^(\n|\r|\r\n)$|^$' | sed -e 's/^/"/' -e 's/$/"/' | tail -n +2

### STUN ###
This corpus was initially assembled from the STUN unit tests, together
with a crash that it found relatively quickly.

### RT(C)P ###
This corpus was initially assembled from the unittests. RTCP was
minimised first.

There is also rt(c?)p-corpus-with-extra-byte, in which each sample is
prefixed by the byte 0xff. Some of the rtp fuzzers need to decide
which header extensions to enable, and the first byte of the fuzz data
is used for this.

### PseudoTCP ###
Very small corpus minimised from the unit tests.

### SCTP ###
This corpus was extracted from a few manually recorder wireshark dumps.