DTS-Core vs DTS-HDMA. Difference?

[tman24]

I've been playing around with extracting DTS-Core and the full DTSHD-MA to flac from blu-ray disks using eac3to. Using the Sonic decoder, it works well extracting full DTSHD-MA, and libav extracts the DTS-Core fine.

My question is, what is the actual difference between DTS-Core and DTSHD-MA? I understand a 'core' bitrate is around 1.5Mb/s, but DTSHD can be anywhere up to 3-5Mb/s from my experience. Oddly, when I extract the different audio streams, I'm not seeing much of an increase in filesize between the two. For example, a 24-bit 48Khz DTSHD-MA track might be 2.5GB after demuxing, and the equivilant DTS-Core track might only be 200MB smaller.

Is this what I should be expecting from a lossless audio track that is the same as the studio master. Is the DTS-Core track also lossless?

[tebasuna51]

My question is, what is the actual difference between DTS-Core and DTSHD-MA? I understand a 'core' bitrate is around 1.5Mb/s, but DTSHD can be anywhere up to 3-5Mb/s from my experience. Oddly, when I extract the different audio streams, I'm not seeing much of an increase in filesize between the two. For example, a 24-bit 48Khz DTSHD-MA track might be 2.5GB after demuxing, and the equivilant DTS-Core track might only be 200MB smaller.

I can't understand. A 2.3GB DTS-Core track at 1.5Mb/s is 3h 30m.
Are you sure the dts core is 2.3GB?

[nautilus7]

I've been playing around with extracting DTS-Core and the full DTSHD-MA to flac from blu-ray disks using eac3to. Using the Sonic decoder, it works well extracting full DTSHD-MA, and libav extracts the DTS-Core fine.

My question is, what is the actual difference between DTS-Core and DTSHD-MA? I understand a 'core' bitrate is around 1.5Mb/s, but DTSHD can be anywhere up to 3-5Mb/s from my experience. Oddly, when I extract the different audio streams, I'm not seeing much of an increase in filesize between the two. For example, a 24-bit 48Khz DTSHD-MA track might be 2.5GB after demuxing, and the equivilant DTS-Core track might only be 200MB smaller.

Is this what I should be expecting from a lossless audio track that is the same as the studio master. Is the DTS-Core track also lossless?
You have messed things up...

Sonic decoder decodes the full dts-hd information, while libav decodes only the dts-core. Resulting wav files will have exactly the same size and flac files the size difference you mention, since there's less "info" decoded.

The bitrates you mention stand for the dts(-hd) tracks as they are, not decoded.

[tebasuna51]

The size of flac files must be similar, of course.

[nautilus7]

200 MB difference. It is similar, isn't it?

[tman24]

I was extracting the DTS core track using libav BEFORE even having Sonic installed. eac3to said 'extracting dts core...." during demux, and indeed, the resulting file is only 200MB smaller than the same extraction using Sonic which is processing the full HDMA stream.

There's not a lot to mess up. I presume DTS core is still 24-bit 48Khz, but the difference in size is still nowhere what I expected.

I also tried a DTSHD-MA stream (24bit, 48Khz) from a longer movie with a powerful soundtrack. DTS-Core file was 3.2GB, DTSHD-MA file was 3.5GB. This is a straight demux, no downsampling, or downmixing. Still not as much as I was expecting. Maybe there isn't that much more 'information' in a HDMA track after all....

[tman24]

You have messed things up...

Sonic decoder decodes the full dts-hd information, while libav decodes only the dts-core. Resulting wav files will have exactly the same size and flac files the size difference you mention, since there's less "info" decoded.

The bitrates you mention stand for the dts(-hd) tracks as they are, not decoded.

I understand there is 'less' info decoded in a DTS-Core flac trac, but I was curious how much less considering the file sizes are so close, or how much more info is there in a DTSHD-MA stream over DTS-Core at the same bit depth and sampling rate.

I'm not an expert in this at all, it's just an observation on my part, so I thought I'd ask the experts.

[tebasuna51]

We have a 2 hours 5.1 48 KHz audio track.

The DTS core (1.5Mb/s) is 1.3 GB
The DTS-MA (3Mb/s) is 2.6 GB
(Don't exist DTS or AC3 with 16 or 24 bits, the dynamic range equivalent is always 24 bit)

The wav files (PCM uncompressed format) from both streams (24bit, 5.1, 48 KHz) is always 5.8 GB

When you compress these wav files with flac the second (from DTS-MA) is a little more complex (more high frequencies) and you can obtain less compression (45% from wav file) than the first one (40%) then the sizes can be, for instance:
Flac file from DTS core 2.3 GB
Flac file from DTS-MA 2.6 GB

Like you can see the flac size and the DTS-MA file must be equivalent, and transcode a lossy format DTS core to lossless format FLAC only spend bytes.

[tman24]

Thanks for the explanation. I don't use the WAV format, I go straight to flac.

So, even though FLAC is a lossless audio codec, it still uses compression to store the audio stream, and because DTSHD-MA is a more complex format, the compression is less than DTS-Core. Because the are both compressed though (in the flac container), the file sizes are not that dissimilar.

Am I interpretting this correctly?

[tebasuna51]

Thanks for the explanation. I don't use the WAV format, I go straight to flac.
eac3to don't write the wav file in disk, but send the 5.8 GB of PCM uncompressed audio data to flac in both cases. And flac only see one stream more difficult than other to compress.

Go straight to flac only differ in don't write wav file in disk (less disk space used and less time used)