Opened 4 years ago

Closed 4 years ago

#2951 closed defect (needs_more_info)

Crashes when post-processing streams decoded with "mpegvideo"

Reported by: BlackWarren Owned by:
Priority: normal Component: undetermined
Version: unspecified Keywords:
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


Summary of the bug:
If one attempts to post-process a stream decoded with "mpegvideo.c", you get a hardware access violation because "ff_mpv_export_qp_table" sets "offset" to an odd value and subtracts it from "ref->data", causing that previously-aligned pointer to become odd. That odd pointer is later used as the "QP_store" argument to "pp_postprocess", which casts it to a "uint32_t *" and attempts to dereference it.

How to reproduce:
Attempt to postprocess a stream decoded with "mpegvideo".

Change History (4)

comment:1 Changed 4 years ago by BlackWarren

"subtracts" --> "adds", sorry.

comment:2 Changed 4 years ago by cehoyos

If the crash is reproducible with ffmpeg (the command line application) please provide the command line (including complete, uncut console output), if a program using the libraries is necessary, please provide source code.
In any case, please provide gdb output as explained on

comment:3 Changed 4 years ago by BlackWarren

Sorry, I don't know which live streams cause the error, just that some do. At any rate, I don't need a fix, as I have a workaround -- just trying to help FFMPEG by reporting the bug and explaining how it can be easily seen in source code. Thanks....

comment:4 Changed 4 years ago by cehoyos

  • Resolution set to needs_more_info
  • Status changed from new to closed

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