声道 Sound Channel 是指声音在录制或播放时在不同空间位置采集或回放的相互独立的音频信号,所以声道数也就是声音录制时的音源数量或回放时相应的扬声器数量。
声卡所支持的声道数是衡量声卡档次的重要指标之一,从单声道到最新的环绕立体声。
ffmpeg -i audio.aac -ac 1 audio_single.aac
ffmpeg -i audio.aac -map_channel 0.0.0 audio_left.aac -map_channel 0.0.1 audio_right.aac
ffmpeg -i audio.aac -filter_complex channelsplit=channel_layout=stereo audio.mka
ffmpeg -i audio_right.aac -ac 2 audio_right_2.mka
ffmpeg -i audio_left.aac -i audio_right.aac -filter_complex "[0:a][1:a]amerge=inputs=2[aout]" -map "[aout]" audio_amerge.mka
ffmpeg -i left.aac -i left.aac -i left.aac -i left.aac -i left.aac -i left.aac -filter_complex "[0:a][1:a][2:a][3:a][4:a][5:a]amerge=inputs=6[aout]" -map "[aout]" audio_5.1.aac
ffmpeg -i audio.aac -filter_complex volumedetect -c:v copy -f null /dev/null
ffmpeg -i audio_left.aac -filter_complex "showwavespic=s=1920x1080" -frames:v 1 left_wave.png
ffmpeg -i audio_5.1.aac -filter_complex "showwavespic=s=1920x1080:split_channels=1" -frames:v 1 audio_5.1_wave.png
ffmpeg -i audio.aac -filter_complex "atempo=tempo=0.5" -acodec aac audiotempo0.5.aac
ffmpeg -i audio.aac -filter_complex "atempo=tempo=2" -acodec aac audiotempo2.aac