From: Anton Khirnov <anton@khirnov.net>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Cc: Frank Plowman <post@frankplowman.com>
Subject: Re: [FFmpeg-devel] [PATCH v2] lavc/vvc: Error if SPS ID is duplicated within CVS
Date: Sun, 07 Apr 2024 08:15:12 +0200
Message-ID: <171247051281.28449.5799177261707982675@lain.khirnov.net> (raw)
In-Reply-To: <20240406134546.61454-1-post@frankplowman.com>
Quoting Frank Plowman (2024-04-06 15:46:09)
> Key line from the spec is:
>
> "All SPS NAL units with a particular value of sps_seq_parameter_set_id
> in a CVS shall have the same content."
>
> Prior to this patch, the VVC decoder's behaviour on encountering a
> duplicated SPS ID (within the entire bitstream, not restricted to
> a CVS) was simply to replace the entry in the SPS lookup table with the
> new data. Illegal bitstreams with multiple SPSs in the same CVS sharing
> an ID but differing elsewhere could cause all manner of issues.
>
> The patch tracks which SPS IDs have been used in the given CVS using the
> new sps_id_used field of VVCParamSets. If it encounters an SPS with an
> ID already in use and whose content differs from the previous SPS, it
> throws an AVERROR_INVALIDDATA.
I wonder if it wouldn't be better to do what H264/HEVC do, which is
replace the SPS, invalidate the PPSes that depend on the old one, and
start a new CVS.
--
Anton Khirnov
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next prev parent reply other threads:[~2024-04-07 6:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-06 13:46 Frank Plowman
2024-04-07 2:39 ` Nuo Mi
2024-04-07 6:15 ` Anton Khirnov [this message]
2024-04-07 12:13 ` Nuo Mi
2024-04-07 12:16 ` Anton Khirnov
2024-04-07 13:04 ` Nuo Mi
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