Category Archives its HDTV

Freebox supports DTS Neural

Following the announcement of the partnership with DTS in April 2012, Free announced the support of DTS Neural Surround, a process that can take advantage of a 5.1 sound that is transported within a matrixed stereo stream and must LtRt be specifically treated upstream and distribution "for an equivalent rate, channels and VOD portals can now offer HD 5.1 sound." Note that the Freebox is not the first to include this technology since the Bbox Bouygues Telecom already offers this feeling since September 2013. Which content is concerned? A priori, on Freebox, DTS Neural contribution will be exclusively for VOD.


Recommendation R128

After a long work in the Ploud EBU group that brings together the various players in the Broadcast in Europe, the recommendation is finalized R128, online here, on the EBU website. Read also the excellent educational document "On the way to nirvana loudness" of Florian Camerer here.

To summarize here the main lines

To characterize the audio signal, the following parameters are used:

- Measurement of program loudness (loudness program)

- The excursion of loudness (loudness range, LRA)

- Peak level of the signal (maximum true peak level)

There are three types of measures:

- Instantaneous measurement (momentary loudness): sliding window of 400 ms

- The short term measures: sliding window of 3 s

- The infinite measure (integrated loudness) over the lifetime of the program

The value of the measurement of program loudness is normalized to -23 LUFS + - 1 LU

LUFS The scale is equivalent to LKFS scale (K weighting curve or R2LB) with the following correspondence

LU = 0 -23 LUFS

Two scales are used for the metering:

- EBU +9 scale, the default scale, ranging from +9 to -18 LU LU (-41 LUFS - 14 LUFS)

- EBU 18 scale ranging from -36 to + 18 LU LU (LUFS -59, -5 LUFS)

The audio signal to be measured in its entirety, without considering specific elements such as dialogues

The measurement must incorporate the use of the gate, whose relative threshold is 10 LU below the loudness value, obtained by measurement instant (400 ms). Also note the presence of a gate to the silences, the threshold is set at -70 LUFS.

The loudness range (LRA), translated the tour loudness during the program, the measurement algorithm fontionne retained on the statistical distribution of values ​​between 5% and 95%, thus excluding extreme values. The LRA has no value imposed in the R128 standard, it is just recommended not exceed 20 LU for distributing broadcast programs with high dynamic (the film, classical music).

Towards a new loudness normalization EBU / UER


The group EBU / UER Loudness P / LOUD, orchestrated by Florian Camerer, working for some time on new standards for measuring loudness. The IBC's lounge was an opportunity for further discussions on these standards. In short, this is what we can learn from these first recommendations:

MAX normalization of peaks at -1 dBFS true peak

3 time constants for the measurement of loudness:

long term (infinite), use of a measurement with gate so do not take into account the low level crossings

gate threshold = 7 LU below the measured loudness or absolute value (please specify)

short term 10 or 8s

momentary between 100 and 500 ms

target value of loudness = - LKFS 23 + - 1 LU

taken into account for the measurement of the LFE

Read more: P / LOUD

Standard CSA CST-RT-019 HDTV

This new standard, being signed, complements the recommendation CST - RT 017 to define the methodologies for evaluating the sound dynamics.

- Scaling loudness measurement: LKFS curve weighting Leq (R2LB)

weighting ITU-R BS.1770-1

- Average level dialogue s LKFS -25 + - 2 dB


- Measurement methodology of e dynamiqu

we allow loudness of the following excursions:

s for dialogue: + - 7 dB measured in short term around the Dialog level

for all the sound elements of the program: + - 12 dB measured in short term around the Dialog level

Management ridges mixing 5.1 -3 dB FS (forward generalized to all mixer versions, 5.1, LtRt, LoRo, Dual Mono)


information and diagrams from the technical recommendation CST-RT-019-TV-2009-V1

More: CST

SoundCode Dolby E Neyrinck


cf audio Neyrinck

Neyrinck Audio has to provide his SoundCode application for the Dolby E encoding This tool, developed for pro tools and as a standalone application, is a sort of update for Broadcast SoundCode released last year. It can encode and decode a Dolby E file so that it can export a file MBWF (carrying files 8 audio channels, the 5.1 format + 2) interleaved pcm incorporating metadata for Dolby DP600 Dolby encoding used for E, Dolby Digital, Dolby Surround and for analysis and loudness correction. Note the ability to import and export in pro tools of MBWF interleaved files for the 5.1 whose size is greater than 4GB (RIFF64).

A test, learn more audio Neyrinck


cf Neyrinck Audio

Dolby E encoder Surcode Minnetonka


Minnetonka has just released the long-awaited famous Dolby E encoder. Until then, we could decode a Dolby E format in Pro Tools or VST or as standalone application ... Today we can be encoded. The use is very simple, just provide the metadata to the application that will make a Dolby E .wav file, the metadata for the time being obtained through the DP570 (Dolby pending a plug-in version so ...). We tested in AudioSuite encoding in pro tools and decoding without any problems. Finally, we lack the simulation of DRC metadata to populate these because we Dolby Media Meter and LM5D for measuring the loudness and Surcode Pro Logic 2 Minnetonka that simulates LtRt format. Surcode runs in AudioSuite, RTAS for Pro Tools, VST and as a standalone application with AudioTools AWE.

The various programs are supported including Dolby E 5.1 ​​+ 2, a Metadata Import option to import metadata from an XML file or a .wav file containing the chunk DBMD.


Minnetonka Audio cf.

It remains to synchronize the Dolby E .wav file with the HD video streams in compliance with Dolby standards (good positioning of Dolby E data on the sample 37 and proper positioning of the Dolby E .wav file in the reproductive system to the SDI output) , a point which remains delicate.

More: Minnetonka Audio LtRt

Update on 5.1 encoding tools and measuring loudness in pro tools

Pro tools remains one of the most suitable for producing multi-channel software offering many treatment options 5.1 as plug-ins developed by many manufacturers (TC electronic, Dolby Laboratories, Audio Minnetonka, Neyrinck, Soundfield, Waves ...)

Among those tools that fit in a fun way in our mixer 5.1, the TC electronic LM5D is essential to be insert in our master 5.1. It gives us the history of loudness (LeqRLB), its instantaneous value and the average value ("center of gravity") over the life of the program (no sliding window of 10 seconds measuring method "short term" used by the DP570). We also have access to a kind of deviation, "consistency", which gives us information on the change in loudness over the duration of the program: we have a constant loudness or highly variable? Ppm level measurement is accurate and complete what we lack in pro tools, precise measurement of the levels. The LM5D differs from LM5 by this statistical information. For measurement of the center channel with the dialogues, just cut another bus from our master 5.1. The LM5D was recently presented at IBC, and has recently become available for download on the manufacturer's website.

Among the new newly developed plug-ins, we Minnetonka Dolby E audio overcodes of RTAS that allows us to decode a Dolby E stream; the tool is also available as a standalone application Minnetonka AudioTools AWE. We could test it on different sizes (5.1, LtRt) (2 + 2) (5.1). This tool gives us the metadata informed about the various programs. Just insert the plug-in in a track to 7.1 and route the track to a 7.1 bus that will monitor the 5.1 and LtRt via the input respectively to 5.1 and stereo formats.

The limitations of the plug-in is unable to export at present metadata to the DP570 and the inability to decode the Dolby E stream in the timeline, we are obliged to indicate in the browser Dolby E file interlaced .wav (sync occurs at the beginning of the session or if the TC TC is integrated into the Dolby E stream). A settings page brings up the port that would carry these metadata on the external DP570 but for now is not operational. We can reverse the order of bus, in the settings page for working with different standards smpte, movie ...

The LtRt from Dolby E can itself be decoded by another tool developed by Minnetonka Audio, Dolby Pro Logic Surcode 2. This plug-in gives us access to different parameters (fashion movie or music, panorama ...) Pro Logic 2 decoder as it can encode in LtRt with a limiter and a gain for LR LSRs C and LFE.

It is also possible to encode and decode a Dolby Surround format in pro tools thanks to plug-in TDM format developed by Dolby, Dolby Surround Tools. It can encode a LtRt from a Dolby Surround LCRS format and decode in prologic 1.

In the family of plug-ins to encode into pro tools we have the audio Neyrinck SoundCode. The Dolby Digital SoundCode can encode and decode Dolby Digital.
We must educate metadata (dialog level, downmix, DRC ...) measured at this time by our DP570. The plug-in requires the same settings for the DRC Line Mode and RF Mode strangely. The decoder can decode Dolby Digital stream .wav exported directly in the Pro Tools timeline RTAS, he just have to import our stereo file to a stereo track and put the plug-in insert. This method can also be used to decode a Dolby Digital stream from a DVD player. In the window of the decoder, we can simulate the stereo and mono downmix however the DRC modes do not seem completely controlled. We could not listen without DRC (?). This remains a very good tool to encode Dolby Digital. The tool also exists for DTS, DTS SoundCode his name.

There are also stand-alone applications in audio Minnetonka, Surcode, allowing you to encode Dolby Digital, Dolby Surround, and DTS for audio and qu'encoder DVD (Disc Welder).

Another tool, the SoundCode for Broadcast is also very useful, developed by audio Neyrinck. It helps prepare the encoding Dolby E or Dolby Digital for the DP600 as files. We inform our metadata for both programs and LtRt and 5.1 can export all audio and Dolby metadata in form of .wav file compatible with the DP600. The player SoundCode we can import our Dolby E file from the DP600 and integrate it into pro tools.

cf Neyrinck

Another very interesting feature of SoundCode for Broadcast, is the ability to export and import it into pro tools of RF64 files. We can export multichannel interleaved files 6 tracks for now much larger than 2 GB for long-term programs.

cf Neyrinck

Dolby has developed the software version of LM100, Dolby Media Meter. This measurement software is available as a standalone Mac / PC or to Pro Tools RTAS / AudioSuite Minnetonka AudioTools or AWE. This plug-in allows us to measure the loudness with Dialogue Intelligence technology to automatically detect the passages with dialogues. The measurement can be made on the Dolby Digital audio format, Dolby Digital Plus, Dolby True HD, Dolby E, and PCM.

We have to wait for the audio to Dolby E encoder Minnetonka (before year end?) With the equivalent in soft DP570 to simulate the metadata in pro tools, we can always dream!

The documents of this article are from: Dolby Laboratories, Neyrinck, Minnetonka Audio, TC electronic Digidesign.

Tests on the upmix processor Isostem

Isostem is a broadcast upmix processor for HDTV channels, it is based on an acoustic principle with a downmix "ISO" equal to the stereo. Its manufacturer, Antoine Hurtado, has developed a technology upmix based on analysis of acoustic energy exchanges clew which has recently been published AES. We tested the machine on a week by passing different stereo mix, music, sports, pub ...

The hardware unit has 8 inputs and 8 digital outputs AES Sub 25, and is operated using a Windows compatible software. The sound quality is impeccable and spatial parameters far exceed the Dolby Surround decoding technology.

Indeed, the essential and the starting point of the adjustment based on this small window, panoramic PA analyzer, which analyzes the width or real-time de-correlation of the original stereo and isolates somehow the source of its environment.

The work on the settings of the panoramic analyzer allows us to isolate the highly correlated information and extract multichannel LR ghosting to create one center. We proceed in the same way for the surround channels of information with the management level channel extraction channels L and C, R. This setting is dependent on the depth of the panoramic law and the opening angle stereo. The optimization of the adjustment can be made by monitoring the different analyzer parts through the solo and mute.

We then the virtual microphone VM Module, a kind of simulation of a multi-channel sound recording system, which allows the sound image decorrelate through integration periods and directional microphones, the approach is interesting, it adjusts the spatial decorrelation but the time may induce some comb filtering problems.

The ISO Module allows us to optimize the upmix so that the downmix is ​​identical to the original stereo, reintegrating the intermix, the difference between stereo and downmix.

The output module incorporates monitoring functions (different channels of multi-channel, original stereo, downmix Dolby with the same coefficients and intermix) with different ISO options (optimization of downmix), HCF (mitigation Acute rear), SUB (SUB creation by bass management), PHA (phase correction).

Aside from the quality upmix the Isostem also manages several independent stereo streams that can receive different stems (music, ambiance, VO, VI ...) up to 4 stereo inputs that optimizes the sound reproduction the upmix based on different versions available or stems of a program.

A page containing all the adjustment parameters is integrated into the application.

In summary, this process already used for some HD channels in France, including France 2 HD, and HD NRJ12 offers an intelligent and promising solution for broadcasting stereo 5.1 programs. HDTV is needed because the chains are not always broadcast HD 5.1 100% native programs, it will broadcast programs from 5.1 pre-existing content in stereo and stereo stems if the spatial program of interest.

More: Isostem

Specifications for DTT HD, Dolby Digital + / HE-AAC

The HD Forum has released specifications for HD DTT. It is a reference document for the broadcast and reception of channels TF1 HD, France 2 HD and M6 HD. Remember that these three channels will be the first to be broadcast on TNT in 2008. There is a reminder in this document standards and interesting recommendations regarding multi-channel sound.

Note for processing sound (HD Quote Forum):

For their HD channel, publishers are planning to broadcast several audio components (VF, VO, audio description) associated with the video stream. The audio can be mono, stereo or multi-channel at their convenience. Similarly, according to the program, the type of audio can vary between mono, stereo and multichannel. Note that for streams multichannel Dolby Digital + and support the HE-AAC is required, which leads to the receivers can perform downmixing of these codecs on the stereo outputs.

Transcoding a HE-AAC multi-channel component to Dolby Digital or DTS will only be mandatory from December 31, 2009.

Note also the integration of metadata provided in the HE-AAC stream.

Learn more

HD Forum

LM5, plug-in Pro Tools HD measuring Loudness

TC electronic just released a plug-in for Pro Tools HD to measure the loudness of a 5.1 program useful in the context of multichannel broadcasting in HDTV, for example. This measure takes into account the new standard ITU dialog level Leq (RLB) incorporating a more accurate weighting the Leq (A). The plug-in can follow the history of loudness values ​​as it measures the values ​​of PPM programs with different presets. To test !

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