[FFmpeg-user] [ffmpeg-user] Transcode to high bitrate of Dolby TrueHD or DTS-HD Master

Xuebing Wang xbing6 at gmail.com
Tue Jan 6 02:54:40 CET 2015

On Mon, 2015-01-05 at 18:45 -0500, Marcus Johnson wrote:
> Wait, by HBR are you referring to DTS-HD HBR? because the DTS decoder
> doesn't support really anything beyond Core (aka old fashioned dts)

I may be wrong, I think the *precise* definition of IEC 61937 HBR is
(IEC 60598 frame rates at above 192kHz).
* Every IEC 60598 frame consists of 2 subframes (besides IEC 61937 uses
subframe to carry 16-bits of samples).
* Thus, bitrate = 192k * 2 subframes * 16 bits = 6.144Mbps

This conforms to the definition that >6.144Mbps bitrate is HBR. 

In order to get audio stream passing HDMI (there are logics inside HDMI
hardware), there are 2 ways:
-- For non-HBR (below 192k IEC 60598 frame rate), HDMI logic (hardware)
encodes audio stream (input: normal PCM, output HDMI Audio Sample
-- For HBR, by HDMI passthrough (passthrough above encoding done by
hardware) (and encoding is supposedly done by ff_spdif_muxer), and this
is what I am trying to verify.

But, my HDMI receiver only supports TrueHD, DTS-HD Master via HDMI

But, it seems Dolby Digital Plus (E-AC3), (supports up to 15
full-bandwidth audio channels at a maximum bitrate of 6.144
Mbit/s)(quote from wikipedia), thus it is NOT HBR.


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