[mythtv-commits] Ticket #12228: mythtranscode lossless mpeg seg faults in v0.28-pre-2014-gcc58fb0

[MythTV]

#12228: mythtranscode lossless mpeg seg faults in v0.28-pre-2014-gcc58fb0
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 Reporter:  steve_g@…               |          Owner:  jyavenard
     Type:  Bug Report - Crash      |         Status:  infoneeded_new
 Priority:  minor                   |      Milestone:  0.28
Component:  MythTV - Mythtranscode  |        Version:  Master Head
 Severity:  medium                  |     Resolution:
 Keywords:  mythtranscode           |  Ticket locked:  0
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Comment (by jyavenard):

 Replying to [comment:4 steve_g@…]:
 > "using av_copy_packet as you did will leak as the data contained in the
 destination packet is never freed."
 > The destination is "pkt", created with av_new_packet in the constructor,
 and freed with  av_free_packet in the destructor of the class MPEG2frame,
 which is called from the destructor of MPEG2fixup.  We might be losing the
 source packet though.
 >
 > Im working on the backtrace.

 This is not the issue.

 In the current version, the content of the new packet (data) is copied
 into the old packet data. There's no new memory allocation.

 av_packet_copy replaces the old packet data member with the new one. The
 old packet data now dangling.  The code isn't equivalent.
 You must free the old packet before calling copy. Which means that now for
 every copy you need to free the packet, then copy (which will allocate a
 new one and perform the copy.

 This is inefficient and not the way to do things

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Ticket URL: <https://code.mythtv.org/trac/ticket/12228#comment:5>
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