On Thu, Feb 27, 2020 at 5:03 AM jb <j...@kdenlive.org> wrote:
> Hi all,
>
>
> Following a Kdenlive's bug report, I reproducer a crash in transition_mix
> when using a "consumer" producer is inserted in a playlist, if that
> producer has a different fps than current project.
>
>
> Problem is that in consumer_producer, we have that:
>
> static int get_audio(...)
>
> (...)
>
> // if not repeating last frame
> if ( mlt_frame_get_position( nested_frame ) != cx->audio_position )
> {...}
>
> else
> {
> // otherwise return no samples <-- this case seems to be
> triggered when producer fps is different
> *samples = 0;
> *buffer = NULL;
> }
>
> Having a NULL audio frame buffer and 0 samples is not correctly handled in
> transition_mix, leading to a crash in line 195:
>
> memcpy( &self->dest_buffer[self->dest_buffer_count * channels_a],
> buffer_a, bytes );
>
>
> Crash can be fixed by changing consumer_producer.c, adding this at line
> 101:
>
> *channels = 0;
>
>
> It triggers a bypass in transisiton_mix.c, preventing the crash.
>
> Would that be ok or should this better be fixed by changing transition_mix
> ?
>
I think the fix should be in transition_mix.c. How about
--- src/modules/core/transition_mix.c
+++ src/modules/core/transition_mix.c
@@ -141,3 +141,3 @@ static int transition_get_audio( mlt_frame frame_a,
void **buffer, mlt_audio_for
// Prevent dividing by zero.
- if ( !channels_a || !channels_b )
+ if ( !channels_a || !channels_b || !buffer_a || !buffer_b )
return 1;
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