how to decrypt ec3 audio from ism

[m0ck]

It seems like N_m3u8DL-RE or XstreamDL can’t handle EC3 audio files.
I think it’s probably due to a missing init part or something.
Is there a way to work around this? Preferably without complicated hex editing of the audio.

Here’s an example manifest link with the key:

https://ec04-tpix-waw.cdn-canalplus.pl/vod/store01/CAP_21055180/_/hd4-hssdrm02.ism/manifest
9b7813c10af24b71ab6126d70f2451b7:334822fb6db1f9ae032027a9757442d3

[larley]

While N_m3u8DL-RE does support EC-3

FourCC="EC-3"

doesn't seem to be in the official documentation for MSS.

Quote:

When the Type of the StreamIndex element is video, the FourCC attribute indicates the video codec. Supported values are:

- WVC1, which represents the VC-1 codec
- AVC1, which represents H.264 MPEG 4 Part 15. Other synonyms are X264, DAVC, and H264.
- AVCB, which represents H.264 MPEG 4 Annex B

Note that X264, DAVC, H264 values should not be used; instead, use AVC1 as noted in the second bullet point above.

The FourCC attribute indicates the audio codec used. Supported values are:

- WMA, which represents WMA with no version-specific information. For more information, see WAVEFORMATEX structure.
- WMAP, which represents WMA Pro.
- WMA2, which represents Windows Media 9.1-compatible WMA audio.
- AAC, which represents AAC (ISO AAC coding).
- AACL, which represents AAC-LC (AAC low complexity).
- AACH, which represents AAC-HE.
- AACP, which represents AAC+.

And since there's also AAC available you should just use that


Also, when playing it in dash.js on Edge using PlayReady (only player I found to be working), ec-3 audio isn't shown as a selectable option.

[stabbedbybrick]

I can't seem to access the manifest for some reason but if it's anything like Amazon's ISM audio, you can use ffmpeg to add eac3 codec to the file before decryption.

1. Download audio without decrypting it.
2. Run ffmpeg on it:

ffmpeg -c:a eac3 -i audio.mp4 -c:a copy eac3_audio.mp4

3. Use mp4decrypt on the new audio file.

[larley]

There is polish geoblocking on the manifest.
And unfortunately, that Amazon trick did not work, even when trying with 'aac' instead of eac3 (because ffprobe showed this: Audio: aac (ec-3 / 0x332D6365))

A few warnings when running it through ffprobe:

[mov,mp4,m4a,3gp,3g2,mj2 @ 000001f271a71bc0] ignoring 'frma' atom of 'ec-3', stream has codec id 86018
[aac @ 000001f271a83340] Audio object type 0 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001f271a71bc0] Failed to open codec in avformat_find_stream_info
[aac @ 000001f271a83340] Audio object type 0 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001f271a71bc0] Could not find codec parameters for stream 0 (Audio: aac (ec-3 / 0x332D6365), 96000 Hz, 0 channels, fltp, 191 kb/s): unspecified number of channels

Untouched english ec-3 audio file: https://files.videohelp.com/u/307915/eng.m4a

[tad108]

There is polish geoblocking on the manifest.

Hi, if i get this error msg:

ERROR: Failed to get KEY, ignore.: One or more errors occurred. (The 'data' scheme is not supported.)
ERROR: Failed to get KEY, ignore.: One or more errors occurred. (The 'skd' scheme is not supported.)

when trying to download audio via WidevineProxy2 and it fails to decrypt, is it because the audio may be geo restricted? Or just the key provided is not correct?

update: instead of using m3u8, use mpd this could prevent from errors..

[stabbedbybrick]

There is polish geoblocking on the manifest.
And unfortunately, that Amazon trick did not work, even when trying with 'aac' instead of eac3 (because ffprobe showed this: Audio: aac (ec-3 / 0x332D6365))

A few warnings when running it through ffprobe:

[mov,mp4,m4a,3gp,3g2,mj2 @ 000001f271a71bc0] ignoring 'frma' atom of 'ec-3', stream has codec id 86018
[aac @ 000001f271a83340] Audio object type 0 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001f271a71bc0] Failed to open codec in avformat_find_stream_info
[aac @ 000001f271a83340] Audio object type 0 is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001f271a71bc0] Could not find codec parameters for stream 0 (Audio: aac (ec-3 / 0x332D6365), 96000 Hz, 0 channels, fltp, 191 kb/s): unspecified number of channels

Untouched english ec-3 audio file: https://files.videohelp.com/u/307915/eng.m4a

Ah well, it was worth a shot. You'd probably need to properly build the dec3 box in that case.