Category Archives its HDTV

Freebox support DTS Neural

Following the announcement of the partnership in April 2012 with DTS, Free announced the support for DTS Neural Surround, a process that can take advantage of a 5.1 sound that is transported within a matrixed stereo LtRt flow and must be specifically addressed upstream and distribution "for an equivalent flow, chains and gates can now offer VOD in 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:

- Instant measurement (momentary loudness): sliding window 400ms

- The short term measure: 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

The LUFS scale is equivalent to the 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 the dialogues

The measure must incorporate the use of gate, whose relative threshold is 10 LU below the value of the loudness, obtained by measurement instant (400 ms). Also note the presence of a gate for silences, whose 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 outliers. The LRA has no value imposed in the R128 standard, it is just advisable 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:

Standardization MAX 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

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

it allows the following loudness of excursions:

for dialogue s + - 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

managing peaks 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 offer its 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, 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 possibility to import and export in pro tools of MBWF interleaved files for 5.1 whose size is greater than 4GB (RIFF64).

A test, learn more audio Neyrinck


cf Neyrinck Audio

Surcode Dolby E encoder 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. Usage 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 to inform these metadata 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 DBMD chunk.


Minnetonka Audio cf.

It remains to synchronize the Dolby E .wav file with the HD video stream respecting Dolby standards (good positioning of Dolby E data on the sample 37 and proper positioning of 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 best suited for multichannel output 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 the must 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 some kind of standard 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 is lacking in pro tools, accurate measurement of levels. The LM5D differs from LM5 by this statistical information. For measurement of the center channel with the dialogues, just cut other buses from our master 5.1. The LM5D was recently presented at IBC, and has recently become available for download from the manufacturer's website.

Among the new newly developed plug-ins, we Minnetonka Dolby E audio overcodes of RTAS allowing us to decode a Dolby E stream; the tool is also available as a standalone application Minnetonka AudioTools AWE. We were able to 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 Dolby E stream in the timeline, we are obliged to indicate in the browser Dolby E file interlaced .wav (sync is 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, to work 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 (music or movie mode, 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 encodes a LtRt from a Dolby Surround LCRS format and decode in prologic 1.

In the family of plug-ins for encoding in pro tools we have the SoundCode audio Neyrinck. The SoundCode Dolby Digital is used to 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 with 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 application for Mac / PC or to Pro Tools RTAS / AudioSuite or Minnetonka AudioTools AWE. This plug-in allows us to measure the loudness with Dialogue Intelligence technology that automatically detects 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 Dolby E encoder with audio 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 a sound principle with a downmix "ISO" equal to the stereo. Its builder, Antoine Hurtado, has developed a technology upmix based on analysis of acoustic energy exchanges at the listening position that has recently been the subject of a publication 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 the spatialization parameters far exceed the Dolby Surround decoding technology.

Indeed, the essential and the starting point of the adjustment is based on this small window, the panoramic PA analyzer, which analyzes the width or real-time de-correlation of the original stereo and that 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 it from the multichannel LR ghost to create a center. We proceed in the same way for the information of the surround channels with channel management level 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 sort 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 delays can 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 the stereo downmix.

The output module incorporates monitoring functions (the various 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 diffusion 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 Forum citation):

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 multichannel at their convenience. Similarly, depending on the programs, the audio type will 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 mandatory from 31 December 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 has released a plug-in for Pro Tools HD to measure the loudness of a 5.1 program useful in the context of multi-channel broadcast 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 allows you to track the history of Loudness measurement values ​​so that the MPC values ​​programs with different presets. A test!

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