I created the input video in Windows Movie Maker. At 4 seconds in, I inserted a blue image for the duration of 3 seconds. There is no audio associated with those 3 seconds. Instead of the correct silence, the output video has an audio stutter across those 3 seconds that sounds like a fast repeat of part of the audio immediately before the blue image. Input: ffmpeg -i ~/videos/audio_stutter.wmv ~/videos/zout.avi Output: FFmpeg version SVN-r11026, Copyright (c) 2000-2007 Fabrice Bellard, et al. configuration: libavutil version: 49.5.0 libavcodec version: 51.48.0 libavformat version: 51.19.0 built on Nov 14 2007 11:47:14, gcc: 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2) [wmv3 @ 0x84b2a30]Extra data: 8 bits left, value: 0 Seems stream 1 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 30.00 (30/1) Input #0, asf, from '/home/jschmiederer/videos/audio_stutter.wmv': Duration: 00:00:10.0, start: 2.000000, bitrate: 686 kb/s Stream #0.0: Audio: wmav2, 44100 Hz, stereo, 96 kb/s Stream #0.1: Video: wmv3, yuv420p, 640x480, 768 kb/s, 30.00 fps(r) Output #0, avi, to '/home/jschmiederer/videos/zout.avi': Stream #0.0: Video: mpeg4, yuv420p, 640x480, q=2-31, 200 kb/s, 30.00 fps(c) Stream #0.1: Audio: mp2, 44100 Hz, stereo, 64 kb/s Stream mapping: Stream #0.1 -> #0.0 Stream #0.0 -> #0.1 [wmv3 @ 0x84b2a30]Extra data: 8 bits left, value: 0 Press [q] to stop encoding frame= 300 fps= 59 q=31.0 Lsize= 569kB time=10.0 bitrate= 466.5kbits/s video:465kB audio:79kB global headers:0kB muxing overhead 4.839716%