Avidemux can successfully transcode audio to AAC for 25fps and small 50fps AVI files, but does not render large 50fps AVI files correctly.
Steps to reproduce the problem:
1. Using any content, create a large 25fps DV AVI source file (25fps DV video + 128kbps 48kHz stereo PCM audio) of approximately 11s - 12s (~2.4GB)
2. In Avidemux transcode audio to AAC (Video=Copy, Audio=AAC (Faac), Format=AVI, Tools>Preferences>Output>Create OpenDML files checked)
3. Windows applications and VirtualDub can successfully open and play back video and audio from the transcoded file
4. Create a large 50fps DV AVI file (~ 5GB). Use your own procedure or follow these steps (to keep things simple correct colourspace handling is omitted):
4.1. Open the 25fps source file above in VirtualDub
4.2. Select Video>Full processing mode
4.3. In Video>Filters, add only the deinterlace filter, set to Yadif and double frame rate, bottom field first (or any framerate-doubling filter of your choice)
4.4. Set Video>Compression to Cedocida DV Codec 0.22 or a DV encoder of your choice
4.5. Select Audio>Direct stream copy
4.6. Render the 50fps output via File>Save as AVI
5. In Avidemux transcode audio to AAC (Video=Copy, Audio=AAC (Faac), Format=AVI, Tools>Preferences>Output>Create OpenDML files checked)
6. Windows applications may open the file and play video without audio, or may hang
7. Opening the file in VirtualDub with the AAC ACM codec results in the message:
"AVI Import Filter
Reconstructing missing index block"
The results are the same for input AVIs containing Lagarith video and PCM audio.
I have not tried other container types or video or audio transcoding formats.
Avidemux 2.5.6 and Windows 7 32-bit Professional SP1, 2.6GHz Intel Core i5-2540M with 4GB RAM.
have you tried this with 2.6? work have been done since 2.6 r8108 on avi/openDML muxer.
http://avidemux.org/nightly/win32/ or here: http://avidemux.razorbyte.com.au/