Linux Fedora 22 (kernel 4.2.3) with NVIDIA Corporation GK107 HDMI Audio Controller, GeForce GTX 650 video card.
Short description of error
The default settings for Blender are to work with 44.1k sample rate audio. When importing video or audio files with 48k sample rate audio, a high pitch "whine" artifact is introduced. This artifact is subtle, but quite noticeable in quiet sections of the audio.
Exact steps for others to reproduce the error
Import the attached WAV file (or load the "48k_audio_artifact.blend" file). You must then confirm that User Preferences -> System -> Sample Rate is set to the default "44.1k". Now just play the audio.
To "fix" the problem, go to User Preferences -> System -> Sample Rate and set to "48k"
The mvi_6317.wav file was created from a video file recorded using a Canon 650d dSLR which records audio at 48k, I separated the audio to make a simpler test case for you developers, and to make the file sizes smaller. But, the problem exists identically in the original video file, which I can attach if anyone is interested, but it is 285MB.
[lapham@bilbo BlenderBug]$ ffmpeg -i mvi_6317.mov mvi_6317.wav
[lapham@bilbo BlenderBug]$ ffmpeg -i mvi_6317.wav
Input #0, wav, from 'mvi_6317.wav':
Metadata: encoder : Lavf56.25.101 Duration: 00:00:47.18, bitrate: 1536 kb/s Stream #0:0: Audio: pcm_s16le ( / 0x0001), 48000 Hz, 2 channels, s16, 1536 kb/s
Both the original video and audio play on all the normal video/audio apps without this high pitch sound.
I believe that the solution to this bug could be:
- when importing audio at a different sample rate, the user should be warned if the User Preferences -> System -> Sample Rate doesn't match.
- fix the conversion from 48k -> 44.1k to not have this artifact.
Thank you for your time