I was hoping with 0.8.2 the problem would be fixed but it persists. Whenever I try to render with audio the render crashes. Without audio my memory usage jumps to 3/3.2 GB, with audio it goes all the way up to 3.2 GB and then crashes. Tried ac-3 and mp3 in combinations with x264 and MPEG-2, same problem. It doesn't matter if I try it with my current project or open a new one and load random clips with no effects. My melt is 0.7.6-0ubuntu0~sunab~maverick1 as of writing but I use the svn repository and there is an upgrade to 0.7.7 available. This problem started after I upgraded from 0.8.0 to the SVN, I upgraded from 0.8.0 because it was rendering with the proxy clips even with the box unchecked and I had read the SVN fixed that.

Ubuntu version is 10.10 32-bit

If anyone could comment on what might be the problem I'd be appreciative. I'm planning on re-installing ubuntu after I've bought a new hard drive, but I'm probably going to be waiting a little into next year for prices to drop back down. It'll be a good chance to go to 64-bit as I've added 2 GB of ram. The problem started before I replaced my ram.

/var/log/kern.log
Nov 10 09:30:17 adam-desktop kernel: [ 2596.192390] melt[3210]: segfault at 0 ip 00185fb6 sp b5236b38 error 6 in libc-2.12.1.so[110000+157000]

Here is the GDB backtrace:
Starting program: /usr/bin/melt /home/adam/kdenlive/scripts/script001.sh.mlt -profile atsc_720p_2398 -consumer avformat:/home/adam/Desktop/test3.mp4 progress=1 f=mp4 hq=1 acodec=aac ab=192k ar=48000 pix_fmt=yuv420p vcodec=libx264 minrate=0 vb=10000k g=250 bf=3 b_strategy=1 subcmp=2 cmp=2 coder=1 flags=+loop flags2=dct8x8 qmax=51 subq=7 qmin=10 qcomp=0.6 qdiff=4 trellis=1 aspect=@16/9 pass=1 threads=4 real_time=-1 passlogfile=/home/adam/Desktop/test3.mp4.log
[Thread debugging using libthread_db enabled]
[mp3 @ 0x819e1c0] max_analyze_duration reached
[mp3 @ 0x81a5230] max_analyze_duration reached
[New Thread 0xb6fd2b70 (LWP 3338)]
[New Thread 0xb640db70 (LWP 3339)]
[New Thread 0xb5108b70 (LWP 3340)]age: 0
[New Thread 0xb4907b70 (LWP 3341)]
[New Thread 0xb4106b70 (LWP 3342)]
[New Thread 0xb3905b70 (LWP 3343)]
[New Thread 0xb1cd3b70 (LWP 3344)]age: 0
[New Thread 0xb14d2b70 (LWP 3345)]
[New Thread 0xb0cd1b70 (LWP 3346)]
[New Thread 0xb04d0b70 (LWP 3347)]
[New Thread 0xadce4b70 (LWP 3348)]
[mp3 @ 0xd170940] max_analyze_duration reached 8
[mp3 @ 0xd172920] max_analyze_duration reached
Current Frame: 587, percentage: 12
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb640db70 (LWP 3339)]
0x001e0fb6 in ?? () from /lib/libc.so.6
(gdb) backtrace
#0 0x001e0fb6 in ?? () from /lib/libc.so.6
#1 0x001c2a00 in ?? () from /lib/libc.so.6
#2 0x00135b65 in mlt_frame_get_image (self=0xb918e530, buffer=0xb640cc94,
format=0x814680c, width=0xb640cda8, height=0xb640cda4, writable=0)
at mlt_frame.c:453
#3 0x030951d5 in framebuffer_get_image (frame=0xba343430, image=0xb640cdac,
format=0x814680c, width=0xb640cda8, height=0xb640cda4, writable=0)
at producer_framebuffer.c:158
#4 0x00135b65 in mlt_frame_get_image (self=0xba343430, buffer=0xb640cdac,
format=0x814680c, width=0xb640cda8, height=0xb640cda4, writable=0)
at mlt_frame.c:453
#5 0x01a5f656 in deinterlace_yadif (frame=,
filter=, image=0xb640d360, format=0x814680c,
width=0xb640cf2c, height=0xb640cf28, mode=0) at filter_deinterlace.c:120
#6 0x01a5fe54 in filter_get_image (this=0xba342220, image=0xb640d360,
format=0x814680c, width=0xb640cf2c, height=0xb640cf28, writable=0)
at filter_deinterlace.c:220
#7 0x00135b65 in mlt_frame_get_image (self=0xba342220, buffer=0xb640d360,
format=0x814680c, width=0xb640cf2c, height=0xb640cf28, writable=0)
at mlt_frame.c:453
#8 0x03804a6a in filter_get_image (this=0xba342220, image=0xb640d360,
format=0x814680c, width=0xb640d05c, height=0xb640d058, writable=0)
at filter_rescale.c:215
#9 0x00135b65 in mlt_frame_get_image (self=0xba342220, buffer=0xb640d360,
format=0x814680c, width=0xb640d05c, height=0xb640d058, writable=0)
at mlt_frame.c:453
#10 0x03804ff7 in filter_get_image (this=0xba342220, image=0xb640d360,
format=0x814680c, width=0xb640d37c, height=0xb640d378, writable=0)
at filter_resize.c:267
#11 0x00135b65 in mlt_frame_get_image (self=0xba342220, buffer=0xb640d360,
format=0x814680c, width=0xb640d37c, height=0xb640d378, writable=0)
at mlt_frame.c:453
#12 0x0014995b in producer_get_image (self=0xbb16f7a0, buffer=0xb640d360,
format=0x814680c, width=0xb640d37c, height=0xb640d378, writable=0)
at mlt_tractor.c:276
#13 0x00135b65 in mlt_frame_get_image (self=0xbb16f7a0, buffer=0xb640d360,
format=0x814680c, width=0xb640d37c, height=0xb640d378, writable=0)
at mlt_frame.c:453
#14 0x0014995b in producer_get_image (self=0xcfad8, buffer=0xb640d360,
format=0x814680c, width=0xb640d37c, height=0xb640d378, writable=0)
at mlt_tractor.c:276
#15 0x00135b65 in mlt_frame_get_image (self=0xcfad8, buffer=0xb640d360,
format=0x814680c, width=0xb640d37c, height=0xb640d378, writable=0)
at mlt_frame.c:453
#16 0x00145765 in consumer_read_ahead_thread (arg=0x81467c8)
at mlt_consumer.c:725
#17 0x00156cc9 in start_thread () from /lib/libpthread.so.0
#18 0x0023b69e in clone () from /lib/libc.so.6

Edit: A distribution upgrade from 10.10 to 11.04 fixed the problem, I was pretty sure it was something wrong with my system but wasn't sure what and remain clueless. I am very impressed with Kdenlives support for project files, after all the upgrades my project remains intact and renders perfectly now.