ffmpeg 7.0.1 and Windows 7

[cholla]

@ autodidact,
First I found a download of iTunes 8.
I installed it but it does not have the files you listed.

I searched until I found this:
https://github.com/AnimMouse/QTFiles/releases
For Windows 7 32-bit i downloaded this one: QTfiles.7z
If a person has a Windows 64-bit probably this one will be correct but I did not download it:QTfiles64.7z
The QTfiles.7z has exactly the files you listed in your post #54
These worked fine. & worked to create an .aac file with the aac_at codec.
The .aac file with the aac_at codec was slightly larger than .aac file with the libfdk_aac codec.
To my ears the .aac file with the libfdk_aac codec was a little more bass.

[autodidact]

@cholla,
Thank you for sharing your findings. Should be useful for others who want to try the encoder.

[cholla]

@ autodidact,
I'm using the build you created with enable audiotoolbox (aac_at) .
As I posted I added the QTfiles.
It seemed to work correctly & does on some files.

It fails to convert this file correctly:
https://forum.videohelp.com/threads/393684-Converting-to-AAC-5-1-7-1-with-ffmpeg-chang...e2#post2773914
7.1auditionOutLeader_v2_rtb.mp4 (874.1 KB, 15 views)

Using this code:

ffmpeg -i input.mkv -c:a aac_at -aac_at_quality 0 -aac_at_mode vbr -b:a 512k -ac 8  output.mkv

The resulting file shows 8 channel but only has audio on the center channel.
This is from MediaInfo:

Format/Info: Advanced Audio Codec Low Complexity with Spectral Band Replication
Commercial name: HE-AAC
Format profile: High Efficiency AAC@L6

About the same on this file:
DTS_OBJECT_EMULATOR-thedigitaltheater.mkv (408.80 MB, 4 views) posted here
I do get LF C & RF audio but no surround channels
Using this code:

ffmpeg -i input.mkv -c:v copy -c:a aac_at -aac_at_quality 0 -aac_at_mode vbr -b:a 512k -ac 8  output.mkv

Format: DTS XLL X
Format/Info: Digital Theater Systems
Commercial name: DTS-HD Master Audio
Codec ID: A_DTS

If you have the time. Does your version of ffmpeg have different results?
Like all 8 channels working.

[autodidact]

@cholla,
For both test files using your command lines I hear Front Left, Front Center, Front Right. On the first file I also hear the LFE track.

You may have to use a custom channel map. When I try different channel layouts I do hear some surround channels. For example using octagonal on the first file seems to have all channels except LFE. If it is of any help to you, the aac_at codec reports the following supported channel layouts:

[aac_at @ 073fb2c0]   mono
[aac_at @ 073fb2c0]   stereo
[aac_at @ 073fb2c0]   3.0
[aac_at @ 073fb2c0]   4.0
[aac_at @ 073fb2c0]   5.0(side)
[aac_at @ 073fb2c0]   5.1(side)
[aac_at @ 073fb2c0]   6.0
[aac_at @ 073fb2c0]   6.1
[aac_at @ 073fb2c0]   7.0
[aac_at @ 073fb2c0]   7.1(wide)
[aac_at @ 073fb2c0]   quad
[aac_at @ 073fb2c0]   octagonal

[cholla]

I will look into the aac_at codes you posted.
I thought the aac_at was working in the ffmpeg version that you fixed it in.
It does for most files.

I found this out when trying to help eddy89 in this topic:
https://forum.videohelp.com/threads/393684-Converting-to-AAC-5-1-7-1-with-ffmpeg-chang...channel-layout

aac_at can do this because it works with a Mac software eddy89 has used.

apple with afconvert (native from apple)

afconvert -f m4af -d aac -s 0 -b 512000 -q 127 7.1auditionOutLeader_v2_rtb.mp4 apple_afconvert.m4a

The fraunhoffer libfdk_aac worked for this.
I believe it is just a matter of the correct code for ffmpeg.

As autodidact posted octagonal works except no LFE.

ffmpeg -i input.mp4 -c:v copy -c:a aac_at -aac_at_quality 0 -aac_at_mode vbr -b:a 512k -channel_layout octagonal output.m4a

I tried to use ffmpeg channelmap but it always erred.
I could not figure out how to add channelmap to the code.

[autodidact]

Keep in mind that the wrapper that enables the aac_at codec only works within the limitations of the audiotoolbox support in FFmpeg itself.
FFmpeg may not support the full range of audiotoolbox options that a native tool like afconvert does. Maybe eventually it will.

I don't know if this is the problem you are having but to use channelmap, the documentation shows using single quotes:

ffmpeg -i in.mov -filter 'channelmap=map=DL-FL|DR-FR' out.wav

But on Windows you may have to use double quotes around the channelmap.

[autodidact]

Full set of updated FFmpeg builds from git master in post #33.

[pchan]

Free upgrade from Microsoft:
Win 7 to Win 10 (no restriction) - can use all the Windows recent software
Win 10 to Win 11 (TPM 2 and minimum 8thGen Intel CPU)

Getting software to work older Windows OS is getting harder everyday.

[manolito]

Full set of updated FFmpeg builds from git master in post #33.

Hi autodidact,

since your announcement did not mention it I did not really expect that your new versions would take care of my issues with my ancient hardware. Of course I tested the 64bit version anyways, and much to my surprise everything works just fine on my ancient Thinkpad.
Thank you so much!

Cheers
manolito