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manolito · 3rd October 2020, 18:35

The more I dig into these 8-ch audio formats, the more confusing it gets. I am sure glad that I only have a stereo sound system...

I have tested these formats:
DD+ (aka E-AC3) 7.1
DTS-HD MA 7.1
Dolby ATMOS/TrueHD/EAC3

For the DD+ 7.1 format MediaInfo as well as LAV Audio only see 6 channels. This audio format is handled correctly by A2D.

The DTS-HD MA 7.1 format also contains a 6-ch audio stream, and MediaInfo reports it as 8 / 6 channels which causes A2D to issue invalid downmix commands like "Dmix8 / 66()". LAV Audio sees it as 8-ch, so the MediaInfo parsing must be corrected to 8.

For Dolby ATMOS MediaInfo sees 3 audio streams. The first one is ATMOS which right now cannot be decoded by any free audio decoder. So A2D sees it as having 0 channels which of course results in a crash in DownMix.avsi. LAV Audio sees it as 8-ch.

If 8-ch audio is only available in these 3 formats then it should be easy to correct the MediaInfo parsing.

But I found some more confusing facts:
8-ch audio tracks can consist of several audio streams within one track. This concept is rather new to me. MediaInfo 18.05 enumerates the audio as tracks while all FFMpeg based software enumerates the audio as streams. This means trouble for AVStoDVD.

LAV Audio has no way for a user to specify a certain stream from an audio track, it always uses the first stream within a track which it can decode. A specific stream can be selected at playback via LAV splitter (right-click on the splitter tray icon), but I have found no way to select a specific stream within a track for AVStoDVD. So with the exception of DD+ 7.1 LAV Audio will always see 8-ch audio.

If more than one audio track should be included in the A2D project, and the first audio track has 8 channels, the result will be broken. A2D needs to use FFMS2 as the source filter for the second audio track (because DS based source filters do not allow to select the audio track). But if the first audio track contains more than 1 stream, the FFMS2 enumeration will see 2 or more streams in the first audio track pushing up the index numbers. In the case of 2 audio streams within the first audio track the index number for the second audio track will be 3 (instead of 2). This is probably tough to fix.

Cheers
manolito

3rd October 2020, 18:35	#3343 \| Link
manolito Registered User Join Date: Sep 2003 Location: Berlin, Germany Posts: 3,079	The more I dig into these 8-ch audio formats, the more confusing it gets. I am sure glad that I only have a stereo sound system... I have tested these formats: DD+ (aka E-AC3) 7.1 DTS-HD MA 7.1 Dolby ATMOS/TrueHD/EAC3 For the DD+ 7.1 format MediaInfo as well as LAV Audio only see 6 channels. This audio format is handled correctly by A2D. The DTS-HD MA 7.1 format also contains a 6-ch audio stream, and MediaInfo reports it as 8 / 6 channels which causes A2D to issue invalid downmix commands like "Dmix8 / 66()". LAV Audio sees it as 8-ch, so the MediaInfo parsing must be corrected to 8. For Dolby ATMOS MediaInfo sees 3 audio streams. The first one is ATMOS which right now cannot be decoded by any free audio decoder. So A2D sees it as having 0 channels which of course results in a crash in DownMix.avsi. LAV Audio sees it as 8-ch. If 8-ch audio is only available in these 3 formats then it should be easy to correct the MediaInfo parsing. But I found some more confusing facts: 8-ch audio tracks can consist of several audio streams within one track. This concept is rather new to me. MediaInfo 18.05 enumerates the audio as tracks while all FFMpeg based software enumerates the audio as streams. This means trouble for AVStoDVD. LAV Audio has no way for a user to specify a certain stream from an audio track, it always uses the first stream within a track which it can decode. A specific stream can be selected at playback via LAV splitter (right-click on the splitter tray icon), but I have found no way to select a specific stream within a track for AVStoDVD. So with the exception of DD+ 7.1 LAV Audio will always see 8-ch audio. If more than one audio track should be included in the A2D project, and the first audio track has 8 channels, the result will be broken. A2D needs to use FFMS2 as the source filter for the second audio track (because DS based source filters do not allow to select the audio track). But if the first audio track contains more than 1 stream, the FFMS2 enumeration will see 2 or more streams in the first audio track pushing up the index numbers. In the case of 2 audio streams within the first audio track the index number for the second audio track will be 3 (instead of 2). This is probably tough to fix. Cheers manolito