MediaInfo reports:
Audio #1
Count : 321
Count of stream of this kind : 2
Kind of stream : Audio
Kind of stream : Audio
Stream identifier : 0
Stream identifier : 1
StreamOrder : 1
ID : 2
ID : 2
ID in the original source medium : 189-128
ID in the original source medium : 189 (0xBD)128 (0x80)
Unique ID : 16563033064968054267
Format : AC-3
Format : AC-3
Format/Info : Audio Coding 3
Format/Url : https://en.wikipedia.org/wiki/AC3
Commercial name : Dolby Digital
Commercial name : Dolby Digital
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 15136.000000
Duration : 15 s 136 ms
Duration : 15 s 136 ms
Duration : 15 s 136 ms
Duration : 00:00:15.136
Duration : 00:00:15.136
Bit rate mode : CBR
Bit rate mode : Constant
Bit rate : 448000
Bit rate : 448 kb/s
Channel(s) : 6
Channel(s) : 6 channels
Channel positions : Front: L C R, Side: L R, LFE
Channel positions : 3/2/0.1
Channel layout : L R C LFE Ls Rs
Samples per frame : 1536
Sampling rate : 48000
Sampling rate : 48.0 kHz
Samples count : 726528
Frame rate : 31.250
Frame rate : 31.250 FPS (1536 SPF)
Frame count : 473
Compression mode : Lossy
Compression mode : Lossy
Delay : 14948
Delay : 14 s 948 ms
Delay : 14 s 948 ms
Delay : 14 s 948 ms
Delay : 00:00:14.948
Delay : 00:00:14.948
Delay, origin : Container
Delay, origin : Container
Delay relative to video : 14948
Delay relative to video : 14 s 948 ms
Delay relative to video : 14 s 948 ms
Delay relative to video : 14 s 948 ms
Delay relative to video : 00:00:14.948
Delay relative to video : 00:00:14.948
Stream size : 847616
Stream size : 828 KiB (3%)
Stream size : 828 KiB
Stream size : 828 KiB
Stream size : 828 KiB
Stream size : 827.8 KiB
Stream size : 828 KiB (3%)
Proportion of this stream : 0.03317
Title : Surround 5.1
Language : en
Language : English
Language : English
Language : en
Language : eng
Language : en
Service kind : CM
Service kind : Complete Main
Default : Yes
Default : Yes
Forced : No
Forced : No
Original source medium : DVD-Video
bsid : 8
Dialog Normalization : -27
Dialog Normalization : -27 dB
compr : -0.28
compr : -0.28 dB
acmod : 7
lfeon : 1
cmixlev : -3.0
cmixlev : -3.0 dB
surmixlev : -3 dB
surmixlev : -3 dB
mixlevel : 85
mixlevel : 85 dB
roomtyp : Small
dialnorm_Average : -27
dialnorm_Average : -27 dB
dialnorm_Minimum : -27
dialnorm_Minimum : -27 dB
dialnorm_Maximum : -27
dialnorm_Maximum : -27 dB
dialnorm_Count : 372
compr_Average : 4.63
compr_Average : 4.63 dB
compr_Minimum : 0.53
compr_Minimum : 0.53 dB
compr_Maximum : 5.74
compr_Maximum : 5.74 dB
compr_Count : 364
dynrng_Average : 4.62
dynrng_Average : 4.62 dB
dynrng_Minimum : 0.00
dynrng_Minimum : 0.00 dB
dynrng_Maximum : 5.88
dynrng_Maximum : 5.88 dB
dynrng_Count : 372
for the source. The important part is:
Delay : 14948
Delay : 14 s 948 ms
Delay : 14 s 948 ms
Delay : 14 s 948 ms
Delay : 00:00:14.948
Delay : 00:00:14.948
Delay, origin : Container
Delay, origin : Container
Delay relative to video : 14948
Delay relative to video : 14 s 948 ms
Delay relative to video : 14 s 948 ms
Delay relative to video : 14 s 948 ms
Delay relative to video : 00:00:14.948
Delay relative to video : 00:00:14.948
When loading the source Hybrid reports:
" Using container length (30.084) instead of audio length(15.136)"
Mediainfo reports the video length as:
Duration : 29996.000000
Duration : 29 s 996 ms
Duration : 29 s 996 ms
Duration : 29 s 996 ms
Duration : 00:00:29.996
Duration : 00:00:29:29
Duration : 00:00:29.996 (00:00:29:29)
the audio length as:
Duration : 15136.000000
Duration : 15 s 136 ms
Duration : 15 s 136 ms
Duration : 15 s 136 ms
Duration : 00:00:15.136
Duration : 00:00:15.136
and the container:
Duration : 30084
Duration : 30 s 84 ms
Duration : 30 s 84 ms
Duration : 30 s 84 ms
Duration : 00:00:30.084
Duration : 00:00:29:29
Duration : 00:00:30.084 (00:00:29:29)
Looking at the video frames there are ~1800 frames after bobbing, so 30 seconds seems correct.
So the general handling seem correct to me.
Audio is ~15seconds, Video is ~30 seconds. By design the audio starts ~15seconds after the video.
You then tell Hybrid that the delay is 0ms not 14948ms.
Hybrid then does not pass through the delay to the output but still multiplexes ~30 seconds of video with ~15 seconds of audio.
Telling Hybrid to 'keep intermediate' files (or looking at the debug output) one can see Hybrid does change the audio length in any way.
The created audio file has the same length as the original audio file.
Funny thing is, when I simply set the audio delay to 0 I get a file without any noticeable noise
https://www.mediafire.com/file/4iycx7sbc...y.mp4/file.
That is what I initially thought,.. but then I concentrated and my old ears (really not what they used to be, and they were never really good) and noticed there is a slight hissing in the audio, it's not totally silent.
Opening the original with i.e.
audacity and zooming in you can see the audio isn't totally silent, there is some noise.
I then told audacity to normalize the audio to 0.0db, I see:
![[Image: grafik.png]](https://i.ibb.co/DHj353pY/grafik.png)
I also did the same with the 5.1 audio:
![[Image: grafik.png]](https://i.ibb.co/xx5DtH0/grafik.png)
=> This is your static noise you are hearing.
So looking at the calls you used for the audio conversion, there were three:
encoder call: ffmpeg -y -threads 8 -f sox -i - -c:a aac -strict -2 -b:a 512k -ar 48000 -channel_layout stereo "C:\Users\Computer\AppData\Local\Temp\iId_2_aid_1_lang_en_DELAY_-43ms_2025-08-16@20_02_17_7510_02.aac"
decode call: ffmpeg -y -threads 8 -loglevel fatal -nostdin -i "C:\Users\Computer\AppData\Local\Temp\iId_2_aid_1_lang_en_DELAY_-43ms_2025-08-16@20_02_17_7510_01.ac3" -ac 2 -ar 48000 -f sox -
filtering call: sox --multi-threaded --temp "C:\Users\Computer\AppData\Local\Temp\2025-08-16@20_02_17_751001" --buffer 524288 -S -t sox - -b 32 -t sox - gain -n 4.00
The magic is in the filtering call.
What it does, is it applies a +4 dB gain with normalization (no clipping), which causes the near silent hissing to become noticeable.
So what happened is:
a. you removed the delay and told Hybrid to mux a 15 second audio with 30 second video. (so the audio should start at the beginning and end after 15 seconds)
b. your told Hybrid to boost the audio volume
=> Seems like Hybrid did everything as requested. And the audio normalization just increased the audio way more than you expected.
Cu Selur
