It's not clear why we're currently outputting the format in both init()
and consume() - it seems likely that this was accidentally introduced
in <unknown commit>
when we started outputting the format in consume() but didn't remove it
from init().

The SCTE-35 TsExtractorTest doesn't pass with the current code because
when it seeks back to the beginning of the file init() is not called
again so the second pass through only sees one sample (and
ExtractorAsserts checks that seeking back to 0 produces the same output
as reading the file from the beginning).

I generated the SCTE-35 sample using TSDuck's tsp command:
$ tsp --add-input-stuffing 1/10 \
   -I file testdata/src/test/assets/ts/sample.ts \
   -P pmt --service 1  --add-programinfo-id 0x43554549 --add-pid 600/0x86 \
   -P spliceinject --service 1 --files scte_35.xml --wait-first-batch \
   -P filter --negate --pid 0x1FFF \
   -O file testdata/src/test/assets/ts/sample_scte35.ts

This was adapted from the instructions in section 5.2.24.1 of the TSDuck
user manual: https://tsduck.io/download/docs/tsduck.pdf

PiperOrigin-RevId: 296217084