Low/poor sound on DVDs and video files through TV

[techmot]

Hi, does anyone know why alot of commercial DVDs produce very low audio when playing through a TV?. I've found that this isn't just with DVDs but also with HD movies and TV files I have downloaded, and even shows and films on streaming sites. Playing alot of the files through any TV I have in the house you have to really turn the volume right up to 100% just to hear anything, and even then the sound is still very low. Anyone know why this is? you never had this with VHS, and most of my older DVDs going on for nearly 20 years old weren't as bad as this. Is this down to the bitrate or encoding?.

[Subtitles]

I haven't noticed this in my DVD collection
Rip one of the DVD's and check it's audio track amplitude in Audacity. Post a screenshot of a section if you can.
Also check the audio settings in your TV's.

[davexnet]

My old Samsung dvd player had an audio option to reduce the dynamic range...
A lot of possibilities

[TubeBar]

Hi, does anyone know why alot of commercial DVDs produce very low audio when playing through a TV?. I've found that this isn't just with DVDs but also with HD movies and TV files I have downloaded, and even shows and films on streaming sites. Playing alot of the files through any TV I have in the house you have to really turn the volume right up to 100% just to hear anything, and even then the sound is still very low. Anyone know why this is? you never had this with VHS, and most of my older DVDs going on for nearly 20 years old weren't as bad as this. Is this down to the bitrate or encoding?.

Not sure about downloaded files but most commercial DVDs use AC3 Audio compression. The problem with AC3 is the default settings everyone likes to use is -27db if my memory serves me right. What that means is in order to make the size of the audio even smaller they actually lower the volume by 27db (which is huge) and DVD players are supposed to "normalize" that volume and restore it. This varies on players, most don't do a great job at it. This is why people preferred DTS audio.

AC3 is terrible crappy lossy compression, IMO the worst.

[Skiller]

Dolby Digital (AC3) proposes dialogs to be mixed so that they are at an average of -31dBFS. This is much quiter than what TV broadcats typically are at.

For anything that has a great dynamic range, the audio engineer has to stick to this, because otherwise live DRC during playback would not work properly. This is why almost everything on DVD using AC3 is so quiet.
While DRC reduces the dynamic range, the dialogs are still at -31dBFS even with full strength DRC. You can only hope the decoder has some means of boosting the volume beyond that, because as far as Dolby is concerned, you are supposed to increase your volume until it's loud enough...

Btw, it is perfectly possible to encode (stereo) AC3 without DRC metadata and with a neutral Dialnorm value (-31) so that it will playback the same volume as any other audio format, which is pretty much how it's used for broadcast.