DE102008026956A1 - Method for switching between digital TV channels i.e. high resolution digital TV channels, involves receiving complete video signal of digital TV channel at one of receivers at time point, and outputting signal at receiver device - Google Patents

Abstract

The method involves receiving digital TV channels by two receivers of a receiving device, and switching of one of the digital TV channels at one of the receivers into another digital TV channel by a user at a time point. A video signal produced by one of the receivers is outputted from the time point into another time point, where the video signal is selected from a mosaic channel and corresponds to the latter digital TV channel. The complete video signal of the latter channel is received at one of the receivers at the point, and is outputted at the receiver device. Independent claims are also included for the following: (1) a computer program for performing a method for switching between digital TV channels i.e. high resolution digital TV channels at a receiving device (2) a data carrier with a computer program for performing a method for switching between digital TV channels i.e. high resolution digital TV channels at a receiving device (3) a receiver device for performing a method for switching between digital TV channels i.e. high resolution digital TV channels at a receiving device.

Description

The The present invention relates to a method and an apparatus for switching between digital TV channels, in particular between high-resolution digital TV channels, on a receiving device with at least two receivers.

With Introduction of digital television has taken time for the switching between programs compared to analog television extended from nearly 0 seconds to about 2-3 seconds. With the introduction of high-definition television This time again, making a simple switch between two channels can take about 5 seconds. This effect is mainly due to the fact that the current compression method, especially MPEG method, only rarely send full frames (called I frames) to the available transmission capacity optimally exploit. In addition, the respective decoder always first build a data buffer before displaying is started.

Out This reason, after switching must first the next full frame to be awaited. Only after can with the digital processing of data for viewing to be started.

• – Wiedergabe eines Kanals 1,
• – Umschalten,
• – Anzeige eines schwarzen Standbildes und
• – sobald ein neuer I-Frame gesendet wird, wird der Puffer gefüllt und mit der Wiedergabe von Kanal 2 begonnen.

In known methods, the following steps are thus carried out:

• Reproduction of a channel 1,
• - switching,
• - Display of a black still image and
• - As soon as a new I-frame is sent, the buffer is filled and playback of channel 2 is started.

Such a method according to the prior art is shown schematically in the middle line of 1 shown in chronological order. The scale shown in the lower area symbolizes a time axis, eg in seconds. Thus, in previous methods when switching from a first channel at time 1 to a second channel for example. Four seconds, a black image would be displayed and only then the current image of the desired new channel are displayed.

For the Internet television were with the US 2008/0117336 A1 and the WO 2008/057110 A2 have already proposed methods for faster switching between digital channels using an auxiliary channel.

The WO 2008/009245 describes a method for optimizing the switching times between different channels of compressed digital content, wherein when viewing the first channel precautionary video data from one or more additional channels are decompressed. In this case, however, it is only possible to switch quickly to a "foreseeable" prepared channel, for example to the next higher or the last selected channel.

The US 2006/0143669 A1 describes a method for fast switching for digital television, but when switching first a request must be made at the provider, which in turn sends a "boost stream" with stored I-frames.

A reduction of the switching time is also with the US 2006/0045189 A1 disclosed, wherein until the reception of the next I-frame of the destination station, a stored image is displayed.

The US 2005/0229221 A1 describes a method for rapid channel change, wherein a receiving device also caches data from stations that are currently not displayed.

The The above-mentioned known methods are in part with considerable Computing services connected to the receiving device, can the switching time single Lich minimum shorten and / or are relied on a signal feedback to a provider.

The Object of the present invention was now a simple To provide method and a corresponding device, which in the Switching from a first channel to a second channel to the user gives the impression of an immediate change of channel, especially avoids the appearance of a black screen. This is a moving image of the target channel almost immediately after be displayed for switching.

• – Empfangen eines ersten Digital-TV Kanals über einen ersten Empfänger (Tuner 1) des Empfangsgeräts und Ausgabe des Videosignals des ersten Digital-TV Kanals am Empfangsgerät,
• – gleichzeitiges Empfangen eines zweiten Digital-TV Kanals über einen zweiten Empfänger (Tuner 2) des Empfangsgeräts ohne Ausgabe dieses Videosignals, wobei der zweite Digital-TV Kanal ein MosaikKanal ist, der mindestens die Videosignale für den zweiten Digital-TV Kanal enthält,
• – Umschalten von dem ersten Digital-TV Kanal am ersten Empfänger auf einen zweiten Digital-TV Kanal durch einen Benutzer zum Zeitpunkt t₀,
• – Ausgabe eines vom zweiten Empfänger erzeugten Video-Signals vom Zeitpunkt t₀ bis zum Zeitpunkt t₁, wobei dieses Video-Signal aus dem MosaikKanal ausgewählt wird und dem zweiten Digital-TV Kanal entspricht und
• – Empfang des vollständigen Videosignals des zweiten Kanals am ersten Empfänger zum Zeitpunkt t₁ und Ausgabe dieses Videosignals am Empfangsgerät.

The object has been achieved by a method for switching between digital TV channels, in particular high-resolution digital TV channels, on a receiver with at least two receivers, wherein after switching at the time t ₀ on the receiver of a first digital TV channel to a second Digital TV channel, the complete video signal of the second channel is received at time t ₁ , the method comprising at least the following steps:

• Receiving a first digital TV channel via a first receiver (tuner 1) of the receiving device and outputting the video signal of the first digital TV channel on the receiving device,
• Simultaneously receiving a second digital TV channel via a second receiver (tuner 2) of the receiving device without outputting this video signal, the second digital TV channel being a mosaic channel containing at least the video signals for the second digital TV channel,
• Switching from the first digital TV channel at the first receiver to a second digital TV channel by a user at time t ₀ ,
• Outputting a video signal generated by the second receiver from time t ₀ to time t ₁ , this video signal being selected from the mosaic channel and corresponding to the second digital TV channel, and
• - Receiving the full video signal of the second channel at the first receiver at time t ₁ and output of this video signal at the receiving device.

An advantage of said method is that the time between switching, preferably with a remote control, is bridged at time t ₀ from a first channel to the display of the desired second channel by displaying to the user any moving video signals, still images or other information become.

According to an advantageous embodiment of the method, the video signal of the second tuner is a live video scaled up by a scaling unit, which corresponds to the second digital TV channel. This embodiment has the advantage that the user after switching without a time delay, a moving video image (lower resolution) of the desired second channel is displayed, which is replaced at a later time t ₁ upon receipt of the complete video signal of the second channel ,

According to an advantageous embodiment variant, the video signal provided by the second receiver from time t ₀ to time t _{1 is} completely or partially replaced by a video signal of a data memory, the video signal of the data memory being a still image or any moving video sequence, for example an advertising sequence is.

Further Benefits arise when the digital TV channels of one Provider (provider) to the receiving device (receiver) transmitted and video from multiple vendors simultaneously Digital TV channels as Mosaic Channel (HQ Mosaic Channel) for Receiving device (receiver) are transmitted.

According to a development, the video signal generated by the second receiver is selected and enlarged by the scaling unit from a cell of the mosaic channel (HQ Mosaic Channel). In this embodiment, the video image to bridge the transition time when switching from the desired channel corresponding area (cell) of a mosaic channel is selected and enlarged by means of a scaling unit in the receiving device and displayed until the complete high-resolution video signal of the desired second channel (time t ₁ ) received, decoded and displayed. For the user, this creates the impression of an immediate switchover from a first channel to a second channel. In this case, the provider can video signals of multiple digital TV channels using a real-time channel multiplexer composed (HQ Mosaic Channel) and then simultaneously as a mosaic channel (as a preview stream) in parallel to the individual high-definition TV signals or via an independent Transmission path are transmitted to the receiver.

The creation or operation of mosaic channels (also referred to as multi-screen image, multi-screen display, Mix Channel, Multi Screen Display, etc.) is, for example, in the WO 2007/030380 , of the EP 0 598 576 B1 or the EP 0 755 604 B1 described. The disclosure of said published documents is expressly incorporated in the present application.

The generation of a mosaic channel by a provider is particularly in the EP 0 598 576 B1 described. In this case, programs of different channels are displayed at the same time as in the present case, for example by dividing the screen into 16 small screens and in each of the delimited cells a live picture is displayed. Such mosaic channels are particularly, such as. WO 2007/030380 A2 shown, used for interactive applications. Such interactive functions of mosaic channels are not necessarily used for the inventive method, but can be integrated. Thus, existing mosaic channels can be used as a prerequisite to perform the method according to the invention.

For the method according to the invention is of decisive importance Meaning that also transfer data with the mosaic channel which supplies the receiving device with information, in which image areas of the mosaic channel which channel is represented becomes. This is the only way to switch from a channel 1 to a channel 2 on the receiver, the scaling unit from the with a second tuner received mosaic channel the area for the select desired channel 2, enlarge and output the corresponding signal for one frame.

The incoming signals at the second receiver are decompressed as a precaution. This means that the mosaic channel is permanently received and decoded in the background via the second receiver (tuner). The I-frame offset only occurs once when the receiver is switched on to wear. From this point on, the uncompressed version of the mosaic channel is always available via the second receiver and decoder, from which, with the help of the scaling unit, only the desired image detail corresponding to the second channel is extracted. Thus, switching to a second channel can be done with virtually no time delay if that destination channel is included in the mosaic channel.

According to one advantageous variant of the method thus by the provider (provider) the high-resolution digital TV programs Channel 1 to Channel N using the Real-Time Channel Multiplexer to a mosaic channel with the video signals for the channels 1 to N summarized and when switching on the receiving device the mosaic channel signal received from the second tuner from a scaling unit converted into a full screen signal. This full screen then owns a lower resolution than high resolution TV picture.

• – sofort vom Signal des zweiten hochauflösenden Digital-TV-Kanals entnommen und an den Ausgang des Empfangsgeräts weitergeleitet werden,
• – vom Zeitpunkt t₀ bis t₁ gar kein Ton an den Ausgang des Empfangsgerätes weitergeleitet werden,
• – ein zum zweiten hochauflösenden Digital-TV-Kanal passendes Tonsignal vom Mosaikkanal entnommen und an den Ausgang des Empfangsgerätes weitergeleitet werden oder
• – aus dem Datenspeicher entnommen und an den Ausgang des Empfangsgerätes weitergeleitet werden.

According to a further embodiment, an image quality switch in the receiving device switches between the high-resolution video signals from the first tuner (HQ Channel 1 - N) and the signals of the scaling unit and / or the data memory and forwards the signals depending on the switching position to the output of the receiving device. There are many possibilities for the output of the sound. So the sound when switching

• - be taken immediately from the signal of the second high-resolution digital TV channel and forwarded to the output of the receiving device,
• No sound is transmitted to the output of the receiving device from time t ₀ to t ₁ ,
• - Taken to the second high-resolution digital TV channel sound signal from the mosaic channel and forwarded to the output of the receiving device or
• - Removed from the data memory and forwarded to the output of the receiving device.

Of the Mosaic channel can simultaneously, for example, four channels with less Resolution, nine such channels, sixteen such Transmit channels, etc. It must of course not all cells with channels to be occupied. Furthermore, the cells could be inside the Mosaic channels also have different sizes. In individual or all cells, advertising sequences, Still images, text, etc. fed.

the Receiving device must in particular information are present which pixels of the mosaic channel to which channel belong. That's why it can be beneficial if a data channel is run alongside or with the mosaic channel with which the areas of the pixels belonging to the channels are transmitted become. Of course, this information can also be transferred together with the mosaic channel.

For the inventive method is also of Advantage if the provider the position of the channels in the mosaic channel and / or the size of each cell can. Also, the provider can see the location of the channels in the mosaic channel for example, depending on the time of day. Thus, you can the broadcasters and / or the providers decide which channels participate in the fast switching process.

Also Procedures such as the electronic programming guide (EPG) and similar can be used at the receiver to make an assignment to reach the transmitter in the mosaic channel.

One Another aspect of the present invention is a receiving device for carrying out the inventive Process. The receiving device may be similar in basic construction like a digital receiver (also digital decoder or digital receiver) for the decoding of digitally transmitted television and value-added services Cable, satellite or terrestrial antenna, especially in DVB format, be designed. The receiving device can either directly in the playback device, such as a monitor, integrated or as an external device (set-top box) for retrofitting be realized.

The There is a receiving device according to the invention now at least from a first tuner with a connected Decoder, a second tuner with a decoder connected to it, an image quality switch, a scaling unit, a Microprocessor and optionally a data memory.

According to one advantageous development of the receiving device is the scaling unit between the second tuner and the picture quality switcher connected.

one or more of the above-mentioned process steps within the meaning of this invention with the aid of a computer program, which on a computer unit, preferably a microprocessor, in the receiver device is executed. Also a Any designed disk on which such a computer program loaded, an object of the present invention.

Farther is also the receiving device or a corresponding one Module (card) of a computer system on which a computer program is described loaded, subject of the present invention.

The inventive method is thus based on the Idea, about another transmission path, so eg another transponder / tuner or an Internet line, to ask an additional mosaic channel the multiple transmitters simultaneously visualized. This qualitatively lower Channels are through the software in the receiving device when switching initially used to the viewer Immediately one, albeit less high-resolution, video impression to convey. Then as soon as the high-resolution image to Is available, is switched to this. alternative or in addition during the "switching gap" can also Videos, pictures, texts, etc. are displayed in a data memory stored in the receiving device. This data can be permanently stored there or changed by a provider or updated. Conceivable here is a selection by the user. So the "switching gap" can be flexible be designed by the user.

in the Compared to conventional methods, there is the advantage that the switching can really be done in real time and no Delay occurs because the mosaic channel (Preview Stream) permanently decoded and / or uncompressed stands. In addition, the mosaic channel can be like a normal one TV channel to be viewed by the viewer. This is before everything then also useful for the spectators, which use a receiver with only one receiver. The viewer can only have an overview of the mosaic channel get the current shipments and then manually the corresponding Select channel.

Further advantages and details of the method according to the invention will become apparent from the description of the embodiments to context with the 1 to 4 , Show it:

1 the output of video signals over time,

2A the provision of a mosaic channel by a provider,

2 B an embodiment of a receiving device for carrying out the method according to the invention and

3 the schematic sequence of an embodiment of the method according to the invention.

1 shows the outputs of the video signals over time. In this case, the user is first shown a video signal of a high-resolution channel 1 (symbolized by an X). The effect now occurs that a high-resolution video signal for the desired channel 2 (represented by an A) takes place only at time 5 after the reception of a complete high-resolution video signal. During this period, a black screen has been displayed so far. This corresponds to the output of a first HQ decoder, which is connected downstream of a first tuner. At the same time, a mosaic channel is received via a second tuner and decoder which receives low-resolution video signals for channel 1 and channel 2. When switching from channel 1 to channel 2 at time 1 (t ₀ ), the high-resolution video signal of channel 1 is now displayed by the enlarged lower-quality video signal of channel 2, which is provided by the second tuner / decoder and the scaling unit ( see third line in 1 ). As soon as the high-resolution video signal from channel 2 is available at the first tuner / decoder, the low-resolution image from channel 2 is replaced by the high-resolution signal (t ₁ ).

According to an alternative embodiment, the user, who has connected a monitor to the receiving device, could also display a still image stored in the data memory or an advertising sequence from this data memory in the period from t ₀ to t ₁ .

A provider presents using a real-time channel multiplexer 10 from a multitude of high-resolution channels 1 to N a mosaic channel available ( 2a ). The corresponding clipping coordinates for the individual channels in the mosaic channel and / or a "stuffing content", for example advertising sequences, are likewise provided, preferably in a data channel. The channels thus provided by the provider can then be transmitted with a suitable device (uplink facility), for example, to a geostationary satellite (uplink signals). At such a satellite, not graphically represented, these uplink signals are then amplified and, with the aid of a transponder, sent back down to the earth's surface as downlink signals. These downlink signals are then recorded by a suitable satellite receiver at the end user or at a central receiver. According to 2 B become the high-resolution video signals of a first channel, for example. Channel 2, in the receiving device 19 the viewer from a first tuner 20 received and a subsequent decoder 21 decompressed, with the image signal (symbolized by the A) from the output of the receiving device 19 to a monitor 22 and the corresponding audio signal to a loudspeaker 23 is forwarded.

At the same time, using a second tuner 24 the mosaic channel received. The signals are from a decoder 25 processed and the image signals of the mosaic channel to a Skaliertein Ness 26 passed. The clipping coordinates and / or the "stuff content" from the data channel are also from the decoder 25 in the data store 28 directed. The image data of the scaling unit 26 or the data store 28 can then via the image quality switch 27 and over the output of the receiving device 19 to the monitor 22 be issued. The picture quality switcher 27 is controlled by a microprocessor not shown in the drawing. On the microprocessor, the inventive method can run.

The circuit of the image quality switch 27 takes place according to the inventive method, which with the schematic diagram after 3 can be carried out particularly advantageous. After the in 3 In the embodiment shown, a viewer gives a command to change from channel X to channel A, for example via a remote control. The first tuner 20 will now be switched to channel A. If the high-resolution video signal for channel A is already fully available, the high-resolution video signal of channel A is immediately displayed. That is, the image quality switch 27 in this case the signal is sent from the first tuner 20 immediately to the monitor 22 further.

However, if the high-resolution video signal for channel A is not yet fully processed, it is first stored in the data memory 28 searched for the mosaic clipping coordinates corresponding to the low-resolution video channel A (read in the coordinate memory). If such a record is found in the coordinate memory, it is scoped using the scaling unit 26 on the basis of the coordinates a current image (moving live image) cut out of the mosaic channel and enlarged to full screen size and the image quality switch 27 to the monitor 22 forwarded. If, on the other hand, no corresponding detail coordinates for channel A are found, the data memory is used 28 looking for a "stuffing content", such as advertising, (reading in the content store). If a corresponding content is found, this can with appropriate switching of the image quality switch 27 on the monitor 22 are displayed. If no corresponding filler content is found in the content store, a black image will be displayed.

The cut out of the mosaic channel and enlarged Video signal, the fill content, or the black image only displayed until a high-resolution video signal fully prepared is available.

1

providers

10

Real Time Channel multiplexer

11

mosaic channel

12

data channel

13

Uplink unit

14

satellite receiver

19

receiving set

20

first tuner

21

decoder

22

monitor

23

speaker

24

second tuner

25

decoder

26

scaling

27

Image quality switch

28

data storage

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2008/0117336 A1 [0006]
• - WO 2008/057110 A2 [0006]
• - WO 2008/009245 [0007]
• US 2006/0143669 A1 [0008]
• US 2006/0045189 A1 [0009]
• US 2005/0229221 A1 [0010]
• - WO 2007/030380 [0019]
• - EP 0598576 B1 [0019, 0020]
• EP 0755604 B1 [0019]
• - WO 2007/030380 A2 [0020]

Claims (17)

Method for switching between digital TV channels, in particular high-resolution digital TV channels, on a receiver with at least two receivers, wherein after switching at time t ₀ on the receiver from a first digital TV channel to a second digital TV channel the full Video signal of the second channel is received at the time t ₁ , the method comprising at least the following steps: receiving a first digital TV channel via a first receiver (tuner 1) of the receiving device and outputting the video signal of the first digital TV channel at the receiving device, - Receiving a second digital TV channel simultaneously via a second receiver (tuner 2) of the receiving device without outputting this video signal, wherein the second digital TV channel is a mosaic channel containing at least the video signals for the second digital TV channel, - switching from the first digital TV channel at the first receiver to a second digital TV K output by a user at time t ₀ , output of a video signal generated by the second receiver from time t ₀ to time t ₁ , this video signal being selected from the mosaic channel and corresponding to the second digital TV channel and receiving the complete video signal of the second channel at the first receiver at time t ₁ and output of this video signal at the receiving device. Method according to claim 1, characterized in that that the video signal of the second tuner is one of a scaling unit from the mosaic channel is upscaled live video. Method according to claims 1 or 2, characterized in that the video signal provided by the second receiver from time t ₀ to time t _{1 is} completely or partially replaced by a video signal of a data memory, wherein the video signal of the data memory a Still image or any moving video sequence is. Method according to one of claims 1 to 3, characterized in that the digital TV channels of a provider (provider) to the receiving device (receiver) transmitted and video from multiple vendors simultaneously Digital TV channels as a mosaic channel (HQ Mosaic Channel) to the receiver (Receiver). Method according to one of claims 1 to 4, characterized in that the second receiver generated video signal from the scaling unit from a cell of the Mosaic Channel (HQ Mosaic Channel) selected and enlarged becomes. Method according to one of claims 1 to 5, characterized in that from the provider video signals of several Digital TV channels using a realtime channel multiplexer assembled (HQ Mosaic Channel) and then simultaneously as a mosaic channel parallel to the individual high-resolution TV signals or via an independent transmission path be transmitted to the recipient. Method according to one of claims 1 to 6, characterized in that the provider of the high-resolution Digital TV programs channel 1 to channel N with the help of realtime Channel multiplexers to a mosaic channel with the video signals for channels 1 to channels N summarized become. Method according to one of claims 1 to 7, characterized in that an image quality switch between the video signals from the first tuner (HQ Channel 1 to N) and the signals from the scaling unit and / or from the data memory switches and sends the signals to the output of the receiving device forwards. Method according to one of claims 1 to 8, characterized in that the sound during switching - taken immediately from the signal of the second high-resolution digital TV channel and forwarded to the output of the receiving device, - from the time t ₀ to t ₁ no sound the output of the receiving device is forwarded, - taken to the second high-resolution digital TV channel matching sound from the mosaic channel (HQ Mosaic Channel) and forwarded to the output of the receiving device or - removed from the data memory and forwarded to the output of the receiving device. Method according to one of claims 1 to 9, characterized in that the mosaic channel at least four Simultaneously transmits channels with lower resolution. Method according to one of claims 1 to 10, characterized in that beside or together with the mosaic channel a data channel is routed to the areas of the the pixels belonging to the channels are transmitted in the mosaic channel. Method according to one of claims 1 to 11, characterized in that the provider the position of the channels in the mosaic channel and / or the size of the individual Cells can change. Computer program for executing a Method according to one of claims 1 to 12. Disk with a computer program Claim 13. Receiving device for implementation A method according to any one of claims 1 to 12, consisting from a first tuner with a decoder connected to it, a second tuner with a decoder connected to it, one Scaling unit, an image quality switch, a microprocessor and optionally a data store. Receiver according to claim 15, characterized in that that the scaling unit is switched between the second tuner and the picture quality switcher is. Receiver according to claim 16, characterized in that in that on the microprocessor a computer program according to claim 13 loaded.