我還活在 DVD 時代，手上沒有 BD 也沒 player。
會問這個是車上音響可以播 DVD，但每次看 DVD 都要把音量轉大，要切其它訊源又得先轉小免得嚇到自己。

最近想把巧虎用 HANDBRAKE 轉成 MP4 在車上播，HANDBRAKE 有個 GAIN 的選項可以調大聲點，再來試試看。
其它舊的 DVD 影片，可能就不調了。

隨便找了一下，好像是說 DVD 的音量才是合宜的，可以動態配合各式音效。(甚至說是 DVD 以外的訊源太大聲了?)
http://www.dvddemystified.com/dvdfaq.html#3.6.4

[3.6.4] Why is the audio level from my DVD player so low?

Many people complain that the audio level from DVD players is too low. In truth the audio level is too high on everything else. Movie soundtracks are extremely dynamic, ranging from near silence to intense explosions. In order to support an increased dynamic range and hit peaks (near the 2V RMS limit) without distortion, the average sound volume must be lower. This is why the line level from DVD players is lower than from almost all other sources. So far, unlike on CDs and LDs, the level is much more consistent between discs. If the change in volume when switching between DVD and other audio sources is annoying, you may be able to adjust the output signal level on some players or the input signal level on some receivers, but other than that, there's not much you can do.

所以 BD 也是一樣小聲嗎?
大家轉影片檔怎麼設定音訊呢?

剛剛發現 handbrake 預設 bitrate 160 轉出來會破音(不知道是不是實驗時的 source 也是 mp4 的關係)，回家再用 DVD source 試一次。