Recently, I decided to watch the bootleg version of a movie that I had seen at a cinema. I saw this movie when I went on a trip to Chennai last year. I had several hours to kill and I had read an interview by the leading actresses to The Hindu that morning. As I saw the movie on the first day first show worldwide, I was distracted by audience reactions to the horror and by a phone call. (I do not download bootleg versions of new movies as I prefer to see (bad) movies from the 80s or 90s. New movies are too woke.) In this screening, I wanted to see what I had missed. (Answer: Not much apparently.)
The bootleg version had 5.1 audio channels and expectedly the vocals suffered from low volume. In multi-channel audio like this, you cannot just blindly boost the audio levels willy-nilly because you will mess up with the audio mixer's original intentions.
So, I retained the original audio as it is but encoded a second stream with different audio levels. A typical 5.1 audio stream has six audio channels — FL, BL, FC, LFE, BR, FR. FC or Front Center is usually exclusively for vocals. If you want a vocal boost, you need to increase the proportion of the FC channel in the channels of the downmixed audio stream — FL and FR.
# Add a new default audio stream that has
# ⬩ all of front left (FL),
# ⬩ half of back left (BL),
# ⬩ twice of front center (FC) and
# ⬩ all of low-frequency effects (LFE)
# on the left and similarly on the right
ffmpeg -i evil-dead-rise.mp4 \
-filter_complex \
"[0:a:0]pan=stereo|FL=FL+0.5*BL+2*FC+LFE|FR=FR+0.5*BR+2*FC+LFE,extrastereo[a]" \
-map 0:v:0 -map "[a]" -map 0:a:0 -c:v:0 copy -c:a:1 copy \
-disposition:a:0 default -disposition:a:1 none \
evil-dead-rise-encoded.mp4
Movie review
The movie is fine as a standalone. As a sequel to Evil Dead, it lacks a lot of prop-based horror of the first four movies. Instead, there is some impressive mutilation-based horror. The leading ladies were great. The kids' reaction to horrific events was surprisingly calm. I believe the Evil Dead Rise title rise in the beginning was my idea. It is in one of my books … in my description for older Evil Dead movies!
UPDATE
In November 2025, I published a more powerful downmixing script in a post titled:
If your TV does not play default language stream by default, then it is not FFmpeg's fault’.
Become an FFmpeg PRO by reading my book Quick Start Guide to FFmpeg.
- MORE INFO — http://www.vsubhash.in/ffmpeg-book.html
- BUY — https://books2read.com/ffmpeg (common link for all stores)