# No sound from WAV strip when encoding in MP3 (but ok from AAC strip)

Breaking down a bigger question: Output vs Format vs Codec: what is the right combination?

In the same project, I have a WAV sound-only strip originating from a recording and an AAC sound strip coming from an MP4 video. I am overlaying the WAV on top of a picture and then concatenating the video+aac strips. I am sure both are 'visible' (not muted) and they are audible when previewing in the editor:

When I try to render them into a file containing MP3 audio, only the last part (the AAC sound) is audible. When the sound encoder is AAC, both work correctly and can be heard in the result.

I tried various combinations of containers and codecs, all fail to render the first part to MP3.

I am using Blender 2.77 on Linux Mint 17.2 (Ubuntu Trusty 14.04 derivative) and I have libmp3lame installed. There is no problem with the WAV file, it can successfully be converted to MP3 using ffmpeg or online tools.

• Have you tried previous versions of Blender and is this a consistent problem occuring with different source files (cc0-licensed/public domain everyone can use for testing) as well? May 11 '16 at 10:50