WO2005053309A1

WO2005053309A1 - Method for determining propagation time differences between video signals and audio signals on television transmission paths

Info

Publication number: WO2005053309A1
Application number: PCT/EP2004/013383
Authority: WO
Inventors: Lothar Helm
Original assignee: Lothar Helm
Priority date: 2003-11-25
Filing date: 2004-11-25
Publication date: 2005-06-09
Also published as: DE10354973B3

Abstract

In order to determine propagation time differences between video signals and audio signals on television transmission paths, the invention provides that simultaneously generated video and audio characteristic signals are to be transmitted in a time-correlated manner on a common transmission path, which is separate from the television transmission path, to a receiving point of the video and audio signals. The transmitted video and audio characteristic signals are used for determining the current time difference in the transmitted video and audio signals. This time difference represents a measure for the current propagation time difference of the video and audio signals on the transmission path.

Description

METHOD FOR DETERMINING RUNTIME DIFFERENCES BETWEEN IMAGE AND SOUND SIGNALS ON TELEVISION TRANSMISSION LINKS

DESCRIPTION

The invention relates to a method according to the preamble of

Claim 1. Such a method is known from DE 198 58 008 C2.

Synchronous errors (picture / sound offset) are common in all areas of television technology

given. In their entirety, these errors often clearly exceed tolerable limits and result in a reduction in the program quality.

DE 198 58 008 C2 describes a method for determining

Differences in transit times of signals on television transmission lines are known

which in regular succession synchronous signals, consisting of brightness and

Sound pulses are transmitted within the television signal. At the receiving location

the transmitted synchronous signals with the help of a synchronous measuring device

or a corresponding measuring arrangement, for example by means of a two-channel Storage oscillographs, evaluated and the respective time offset measured.

However, the program transmission units also cause it

Synchronous errors that have to be recorded and corrected.

From DE 43 09 651 AI a method for determining the

transmission-related time offset between an image signal and one separately

known sound signal transmitted, without any additional influence

on the audio channel and therefore also during an ongoing transmission

is functional. For this purpose, a is transmitted from the broadband audio signal

band-limited audio signal derived from which time-discrete samples are taken

which are sufficient for the course of the sound signal to be transmitted

characterize. The sequence of the samples taken is transferred to the one to be transferred

Image signal inserted so that these samples suffer the same temporal fate as

the image signal. From the transmitted image signal, the sequence that is also transmitted becomes

taken from samples and with the previously obtained sequence of samples regarding

compared their relative timing. The time offset determined from this represents the

Desired information for the time offset between image and sound signal.

In contrast, the object of the invention is a method of

to improve the type mentioned at the beginning in such a way that Transmission units caused synchronous errors are detected and corrected

can.

This object is achieved by the characterizing features of

Claim 1 solved.

With the method according to the invention it is possible to use a

TV transmission link caused image / sound skew on the basis

to determine almost any image and sound signals to be transmitted and

correct automatically. The method according to the invention is thus

especially for measuring and correcting the Büd / Ton offset of

Transmission routes during the current television program transmission

suitable.

The invention is explained below with reference to the drawings. It

shows:

1 shows a block diagram of a device for generating, transmitting, acquiring and evaluating synchronous identification signals working according to the inventive method; FIG. 2 shows a special embodiment of the device according to FIG. 1, in which the transmission of the synchronous identification signals is provided via a sound or image signal transmission line;

Fig. 3 shows a preferred embodiment of the device of Fig. 1;

4 shows a schematic illustration of applications of the method according to the invention with time correction of the transmitted video / audio signals, and

Fig. 5 is a schematic representation for an embodiment of the generation of synchronous identification signals per television field.

In Figures 1 to 4 is schematically a television transmission route with the

Abbreviation "TV-Ü-track" shown. On the television broadcast

Route image and sound signals ("image" and "sound") are transmitted. To determine the runtime differences between the video and audio signals, the

The starting point of the television broadcasting route is one of the video and audio signals

separate synchronous transmission that cannot be transmitted on the TV transmission line

Identification signal generated.

The synchronous identification signal reflects the time course of the image to be transmitted.

and sound signals and their temporal assignment to each other again. The production

the synchronous identification signals is through the block "synchronous identification data generation"

in Figure 1 or by the block "simultaneously generated image and sound data

Field "indicated in Fig. 3.

The synchronous identification signals are transmitted in parallel to the television transmission

Route over a separate route to the reception location of the television transmission route. The

Transmission of the synchronous identification signals is both in the form of a data signal

1 as well as modulated via television signal transmission

Routes or sound transmission lines possible ("Ü" line) (Fig. 2). Die

Transmission of the synchronous identification signals can be at the same time or at different times

actual picture / sound transmission. At the receiving location, the synchronous identification signals with the information that is

from the analysis of the received image and sound signals and their current ones

temporal assignment result, compared, from which directly on the by the

TV-overlap caused image / sound offset ("t of overlap")

can be closed (Fig. 3).

The synchronous identification signals derived from video materials can be in the form

digital data can be saved. Based on these characteristics

Changes in the image / sound synchronicity, which are caused by further editing of the

Video materials are caused to be measurable.

Sync identification signal generation

The image and sound signals to be transmitted themselves can be used as a synchronous identification signal

as well as characteristic features of the image and sound signals to be transmitted and

their temporal allocation to each other are used.

In the case of using the image and sound signals to be transmitted themselves as

Synchronous identification signal can, for example, the audio signals in the picture content of the transmitted image signals are inserted. The image disturbances generated by this

are not relevant here because such a "disturbed" image signal is not

is reproduced, but only the temporal coupling of the image and

Represented sound signals.

In one embodiment for the synchronous characteristic signal generation, the

Synchronous characteristic signals characteristic features of the image and to be transmitted

Sound signals and their temporal assignment to each other.

The image signal is given by the description of the content of each field

Are defined. (Fig. 5). This is the case, for example, with an image file (JPG).

Likewise, each for the entire half-bath or for different areas

Field an average image level value can be specified. All points one

Image area can be the same or depending on the position

(centered) in the calculation. Leave medium image brightness values

are derived in the same way from the optical reproduction of the image signals.

For the sound signal, the basic principle is to map the envelope. This could be with

special evaluation of particularly distinctive sound signal transitions.

The characteristic data stream contains information for a time interval (field interval) for

the field, as well as for the sound signal sequence of this time range. The temporal

Assignment of the picture and sound signals is thus given.

Do the synchronous identification signals also contain the exact time of occurrence

Video and audio signals at the corresponding transmission location,

Transit times of the image and sound signals can be determined directly. The synchronous identification signals

can contain any other information, for example information about the

Synchronous identification signal generation, the origin and destination of the transmission,

editorial information, organizational information, control commands.

The following advantages result from the synchronous identification signal transmission over a separate transmission path:

The picture and sound signals remain unchanged. Their transfer to

Receiving location is not affected. The picture and sound signals must be at the sending location are only available for generating the synchronous identification signals.

The procedure is independent of the existing television transmission

Systems applicable.

The picture / sound offset caused by the television transmission link can be between

any transmission points worldwide determined exactly and automatically corrected

become. This is the same and independent of each other for all transmission

Stretch possible. So everyone can synchronize with everyone worldwide.

Individual television transmission lines no longer necessarily have to be exactly synchronous.

Ultimately, the synchronicity of the overall transmission is only in the

Responsible for the sending and receiving point.

The television transmission systems are able to work for themselves automatically

establish a synchronous transmission state. Changes in the system

(Emergency circuits, replacement of components, ...) are automatically recorded. The described method is universal for measuring and automatic

Correcting the picture / sound offset of all television transmission lines, in particular also

the television program transmission routes suitable.

There are particular advantages if the synchronous identification signals one

Transmission system can be recorded and expanded centrally. Based on

of the synchronous identification signals, the synchronous behavior of the overall system and the signal transit times of the individual transmission links are current and clear

represented. System faults can be reacted to immediately and quickly. The image and sound transmission can also z. B. regarding

minimal signal runtimes by selecting the transmission path with the television

Transmission line can be optimized with the minimum transit time.

Automatic runtime correction

The transit time differences of the image and

Sound signals can be compensated for by an additional delay element 11.

By means of a signal distributor 12, the image / sound signals are synchronized Evaluator 14 and at the same time the transceiver 14 via another

Signal distributor 13 provided. Based on the transferred

Synchronous identification signals are determined by the synchronous evaluator 14 by the

Transmission of the signals caused temporal offset of the received image /

Sound signals. This time offset is made by appropriate settings of the

Compensation element 11 compensates.

The runtime correction by the runtime element 11 can in the example directly

after the Ü section 10 (Fig.4A) or at the destination itself (Fig.4B)

his.

If there are runtime-corrected overlays (Fig.4A) in a row, there is a vote

about the time of correction for each individual transmission route as well as the

How the new setting is advantageous to the setting behavior of the

Optimize the entire system. This vote can be made via appropriate

Control commands are given in the system.

Are the synchronous signals generated at the starting point of the transmission chain

Identification signals along with the image and sound signals to the receiving location

every end user has the opportunity to make corrections to the image

/ Tone run times related to the entire transmission chain.

The runtime corrections of the individual TV transmission lines are preferred

saved. Changes to the settings of the picture and sound signals is now

given.

Runtime corrections for send and receive links.

The large number of transmission links and receiving devices also point

Differences in transit times between the image and sound signal paths. This

Synchronous errors can also be detected and with the inventive method

Getting corrected. The viewer should have the synchronous Büd sound reproduction

taking into account the multitude of transmission and reception paths as well

different receiving devices can be guaranteed. The respective radio and television broadcaster provides for the broadcast

TV programs synchronous identification signals for all users via data networks

(Internet) available. The transmission of the synchronous identification signals could

also integrated into the image / sound data stream via the transmission link itself

become.

The receiving devices determine and save for each television program on the

Based on the synchronous identification signals, the values for synchronous adjustment. This is

also conceivable for the end devices of the viewer himself.

In any case, the video / audio runtime errors of the various broadcasting

Transmission paths and of receiving units, e.g. B. the cable head stations,

Getting corrected. A synchronous reproduction of the Feraseh program signals for

the viewer is guaranteed as soon as the receiving devices reach the viewer

no runtime differences in the implementation of the Büd and sound signals

exhibit.

Claims

PATENT CLAIMS

1. A method for determining the runtime differences between video and audio signals on television transmission links, characterized in that image and sound identification signals generated at the same time are transmitted in a time-correlated manner to one another on a common transmission link separated from the television transmission link to a receiving location of the video and audio signals, and that on the basis of the transmitted picture and sound characteristic signals in the transmitted picture and sound signals, their instantaneous time offset is determined, which represents a measure of the instantaneous difference in transit time of the BÜd and sound signals on the transmission link.

2. The method according to claim 1, characterized in that the sound signal is inserted into the picture content of the television signal to obtain the synchronous identification signals.

3. The method according to claim 1, characterized in that image identification signals and audio identification signals are derived from the image and sound signals to be transmitted.

4. The method according to claim 3, characterized in that the tone identification signal is obtained from the envelope of the tone signal.

5. The method according to claim 3, characterized in that the image identification signal is obtained from an image file of each field of the image signal.

6. The method according to claim 3, characterized in that the image identification signal is obtained from an average level value of each field or from regions of each half-length of the video signal.

7. The method according to claim 3, characterized in that the image identification signal is obtained from average brightness values of the optical reproduction of each field.