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softsyst / qirx_issues

Issue tracker for QIRX
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4.2.1 Stereo shows as Mono #148

Closed jpuigs closed 9 months ago

jpuigs commented 9 months ago

image

Service has stereo sound, Parametric stereo is active, and Mono/Stereo shows Mono ?!?

softsyst commented 9 months ago

Sorry, my crystal ball is just out of service. A friendly remark for you: Such entries are ignored if they do not provide some more info. The least is a raw file of at least one minute, together with a download link posted here,

Thanks for consideration.

jpuigs commented 9 months ago

OK, I thought that watching the attached picture was enough when reading these two contradictory values... Mono / Stereo = Mono Parametric Stereo = Yes

Here you have 1 minute recording. https://we.tl/t-2g8g5qbifW Affected services are all of them, note that some services still don't work,

softsyst commented 9 months ago

Thanks for your immediate feedback and the raw. Everything looks ok. It is a Stereo audio, encoded as Parametric Stereo.

Wikipedia writes: "Parametric Stereo digitally codes a stereo audio signal by storing the audio as monaural alongside a small amount of extra information"

The AAC encoder creates from the stereo input a mono signal, which QIRX correctly indicates as such. The AAC decoder (libfaad, in QIRX residing in the separare exe called qirx_audio) re-creates the Stereo. If you look at the "Audio" tab you will see that the audio decoder created Stereo:

image

Apart from this, the SId's of the services seem to be not conforming to the Standard ETSI TS 101 756 V2.4.1 (2020-08). The upper four bits should be 0xF, for France (together with the correct ECC of E1), not 1, 8, B, D, or E. See Table 3 in that document.

jpuigs commented 9 months ago

Ok, understood. I know what is a parametric stereo signal. It would be comparable to FM MPX signal. A main Mono audio + stereo data (L-R) in a subcarrier.

SIDs are like boleean lottery....... It's a Spanish (Pirate) MUX......

softsyst commented 9 months ago

I already wondered about the Spanish soundtracks...

softsyst commented 9 months ago

Item has been clarified. I close it.