ffmpeg -shortest -y -loop 1 -i test.png -i out.wav -acodec copy -vcodec libx264 result.mp4
ffmpeg version 0.11.1 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jun  9 2012 13:50:13 with gcc 4.7.0 20120505 (prerelease)
  configuration: --prefix=/usr --enable-libmp3lame --enable-libvorbis --enable-libxvid --enable-libx264 --enable-libvpx --enable-libtheora --enable-libgsm --enable-libspeex --enable-postproc --enable-shared --enable-x11grab --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libschroedinger --enable-libopenjpeg --enable-librtmp --enable-libpulse --enable-libv4l2 --enable-gpl --enable-version3 --enable-runtime-cpudetect --disable-debug --disable-static
  libavutil      51. 54.100 / 51. 54.100
  libavcodec     54. 23.100 / 54. 23.100
  libavformat    54.  6.100 / 54.  6.100
  libavdevice    54.  0.100 / 54.  0.100
  libavfilter     2. 77.100 /  2. 77.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, image2, from 'test.png':
  Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: png, rgb24, 1024x768, 25 fps, 25 tbr, 25 tbn, 25 tbc
[wav @ 0x12f80a0] max_analyze_duration 5000000 reached at 5015510
Guessed Channel Layout for  Input Stream #1.0 : stereo
Input #1, wav, from 'out.wav':
  Duration: 00:01:31.14, bitrate: 1411 kb/s
    Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
[buffer @ 0x1361140] w:1024 h:768 pixfmt:rgb24 tb:1/25 sar:0/1 sws_param:flags=2
[buffersink @ 0x13061c0] No opaque field provided
[format @ 0x13045a0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'format'
[scale @ 0x13a0a20] w:1024 h:768 fmt:rgb24 sar:0/1 -> w:1024 h:768 fmt:yuv420p sar:0/1 flags:0x4
[libx264 @ 0x13a0240] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64
[libx264 @ 0x13a0240] profile High, level 3.1
[libx264 @ 0x13a0240] 264 - core 124 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[mp4 @ 0x139fd00] Tag [1][0][0][0]/0x00000001 incompatible with output codec id '65536' ([0][0][0][0])
Output #0, mp4, to 'result.mp4':
    Stream #0:0: Video: h264 (![0][0][0] / 0x0021), yuv420p, 1024x768, q=-1--1, 90k tbn, 25 tbc
    Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, 1411 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (png -> libx264)
  Stream #1:0 -> #0:1 (copy)
Could not write header for output file #0 (incorrect codec parameters ?)