Fix a possible crash in avformat probe #944
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Probe was accessing the cached avformat context from a store pointer (self->child) rather than through the cache. This can result in accesssing released memory if the cache deleted the context. The context pointer should not be saved at all and should only be accessed through the cache system. This change includes a rewrite of the video index change detection so that probe() will not have to access the avformat context at all. This also adds an optimization that if metadata is loaded from XML, and nothing else has changed, then the probe can be skipped.
ddennedy
reviewed
Sep 4, 2023
ddennedy
requested changes
Sep 4, 2023
Stream 0 may not exist. And nb_streams should always be present
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Probe was accessing the cached avformat context from a store pointer (self->child) rather than through the cache. This can result in accesssing released memory if the cache deleted the context.
The context pointer should not be saved at all and should only be accessed through the cache system.
This change includes a rewrite of the video index change detection so that probe() will not have to access the avformat context at all.
This also adds an optimization that if metadata is loaded from XML, and nothing else has changed, then the probe can be skipped.
In my testing, this resolves the crash reported here:
https://forum.shotcut.org/t/beta-version-23-09-now-available-to-test/40558/3