[pulseaudio-discuss] [PATCH] format: Fix rate for HBR passthrough formats

[Alexander E. Patrakov]

There is some Microsoft documentation that contradicts this code.

https://msdn.microsoft.com/en-us/library/windows/desktop/dd316761(v=vs.85).aspx

"""
Dolby TrueHD (MAT)

Dolby TrueHD content is transmitted over IEC 60958 at 176.4 kHz / 8
channels (requiring an IEC 60958 frame rate of 705.6 kHz) for content
sample rates of 44.1, 88.2 and 176.4 kHz, and 192 kHz / 8 channels
(requiring an IEC 60958 frame rate of 768 kHz) for content sample
rates of 48, 96 and 192 kHz.
"""


2018-05-22 12:13 GMT+08:00 Arun Raghavan <arun at arunraghavan.net>:
> In high bitrate mode, we force 192kHz/8ch as the sample format, which is
> the expectation for HBR formats (as that is what allows for the largest
> possible packet size).
> ---
>  src/pulsecore/core-format.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/src/pulsecore/core-format.c b/src/pulsecore/core-format.c
> index 862a74b5d..096acc3a2 100644
> --- a/src/pulsecore/core-format.c
> +++ b/src/pulsecore/core-format.c
> @@ -248,6 +248,9 @@ int pa_format_info_to_sample_spec_fake(const pa_format_info *f, pa_sample_spec *
>
>      if (f->encoding == PA_ENCODING_EAC3_IEC61937)
>          ss->rate *= 4;
> +    else if ((f->encoding == PA_ENCODING_TRUEHD_IEC61937) ||
> +             (f->encoding == PA_ENCODING_DTSHD_IEC61937))
> +        ss->rate = 192000;
>
>      return 0;
>  }
> --
> 2.17.0
>
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-- 
Alexander E. Patrakov