JP4229041B2 - Signal reproducing apparatus and method - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is suitable for use in reading an original sound signal including various types of sounds such as human voices and musical instrument performance sounds from a recording medium and performing variable speed reproduction in a shorter time than the recording time of the original sound signal. The present invention relates to a signal reproducing apparatus and method.

  In the past, we wanted to view the original sound signal including various kinds of sounds such as human voices, musical instrument performance sounds, and natural environment sounds surrounding our lives, such as original sound signals recorded from television broadcasts, in a shorter time. In response to various requirements, various variable speed reproduction methods have been proposed. Among them, as a method capable of real-time processing and little deterioration in human voice quality, there is a method of shortening the playback time by thinning out part of the original sound using the characteristics of the human voice waveform. . Specifically, for example, a method of distinguishing vowel sections, consonant sections, and silent sections of human speech and thinning out silent sections with priority (see Patent Document 1 below), or based on a fundamental frequency of human speech For example, a method of determining a thinning section length.

JP 11-353804 A

  However, in such a conventional method, since the thinning section is determined using the characteristics of human voice, the reproduction quality of human voice during variable speed reproduction can be ensured. In the case of including sound or the like, there is a problem in that noise of a type not included in the original sound signal is generated.

  The present invention has been proposed in view of such conventional circumstances, and reads out original sound signals including various types of sounds such as human voices, musical instrument performance sounds, and natural environment sounds from a recording medium. Thus, it is an object of the present invention to provide a signal reproducing apparatus and method capable of improving the reproduction quality when performing variable speed reproduction in a shorter time than the recording time of the original sound signal.

  In order to achieve the above-described object, a signal reproduction apparatus according to the present invention reads out an original sound signal recorded on a recording medium and reproduces the original sound signal in a shorter time than the recording time of the original sound signal. Thinning means for performing a thinning process on the original sound signal in accordance with the reproduction speed, and a sound pressure in a frequency band lower than a predetermined frequency with respect to the original sound signal before or after the thinning process. Filtering means for applying a filtering process for attenuating the level below a predetermined sound pressure level.

  In addition, in order to achieve the above-described object, a signal reproduction method according to the present invention is a signal reproduction method in which an original sound signal recorded on a recording medium is read and reproduced at a shorter time than the recording time of the original sound signal. A decimation process for performing a decimation process on the original sound signal in accordance with a reproduction speed, and a frequency band lower than a predetermined frequency with respect to the original sound signal before or after the decimation process. And a filtering step for performing a filtering process for attenuating the sound pressure level below a predetermined sound pressure level.

  According to the signal reproducing apparatus and method of the present invention, when the original sound signal recorded on the recording medium is read out and played back at a shorter time than the recording time of the original sound signal, the reproduction speed for the original sound signal is increased. Before or after performing the thinning process according to the above, the original sound signal is subjected to a filtering process for attenuating the sound pressure level in the frequency band lower than the predetermined frequency to a predetermined sound pressure level or less. Even when other signals are included in addition to the desired signal, a waveform that is generated when a signal having a lower frequency component, etc., is reproduced with variable speed while maintaining ease of hearing the desired signal Noise due to distortion can be reduced, and deterioration of reproduction quality can be suppressed.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In this embodiment, a signal reproducing apparatus and method according to the present invention are used to record an original sound signal consisting of a video signal and an audio signal including a performance sound of a musical instrument and a natural environment sound in addition to a human voice. The present invention is applied to a signal recording / reproducing apparatus and method capable of recording and reproducing at a variable speed.

  A schematic configuration of a signal recording / reproducing apparatus 1 in the present embodiment is shown in FIG. Hereinafter, the recording operation of the signal recording / reproducing apparatus 1 will be described first with reference to FIG.

  The system controller 10 controls all the blocks of the signal recording / reproducing apparatus 1. The system controller 10 accesses a ROM (Read Only Memory) 11 and a RAM (Randam Access Memory) 12 via a host bus as necessary, and performs overall control.

  The tuner 14 supplies the video signal and the audio signal input via the antenna 13 to the input switching circuit 15. The input switching circuit 15 is also supplied with a composite video signal and an audio signal from the outside. The input switching circuit 15 supplies a composite video signal to the Y / C separation circuit 16 and supplies an audio signal to an audio A / D (Analogue / Digital) converter 22 in accordance with an instruction from the system controller 10.

  The Y / C separation circuit 16 performs Y / C separation on the composite video signal and supplies it to the switching circuit 17. The switching circuit 17 selects either an S video signal from the outside or an output from the Y / C separation circuit 16 in accordance with an instruction from the system controller 20, and the selected video signal is an NTSC (National Television System Committee) decoder. 18 is supplied.

  The NTSC decoder 18 performs A / D conversion and chroma encoding on the supplied video signal to convert it into digital component video data (hereinafter referred to as video data), and this video data is pre-video signal processing circuit. 20 is supplied. Also, the NTSC decoder 18 supplies a clock generated based on the horizontal synchronization signal of the supplied video signal and a horizontal synchronization signal, a vertical synchronization signal, and a field determination signal obtained by synchronization separation to the synchronization control circuit 19. . The synchronization control circuit 19 generates a clock and a synchronization signal converted to a timing required for each block described later with reference to these signals, and supplies the clock and the synchronization signal to each block.

  The pre-video signal processing circuit 20 performs various video processing such as pre-filter processing on the supplied video data, and the video data after the video processing is sent to an MPEG (Moving Picture Experts Group) video encoder 21 and a post-video signal processing circuit 29. Supply.

  The MPEG video encoder 21 performs an encoding process such as block DCT (Discrete Cosine Transform) on the video data from the pre-video signal processing circuit 10 to generate a video elementary stream (ES), and this video. The elementary stream is supplied to the multiplexing / demultiplexing circuit 25. In the present embodiment, MPEG compression is used, but other compression methods or non-compression may be used.

  On the other hand, the audio A / D converter 22 converts the audio signal selected by the input switching circuit 15 into digital audio data and supplies it to the MPEG audio encoder 23 and the switching circuit 32. The MPEG audio encoder 23 compresses the audio data from the audio A / D converter 22 in accordance with the MPEG format, generates an audio elementary stream, and supplies the audio elementary stream to the multiplexing / demultiplexing circuit 25.

  In the present embodiment, the video data and the audio data are described as being compressed according to the MPEG format, but may be compressed according to another compression format, or may not be compressed.

  The multiplexing / demultiplexing circuit 25 multiplexes the video elementary stream, the audio elementary stream, and various control signals to generate a transport stream, and supplies it to the buffer control circuit 26. The buffer control circuit 26 performs control to intermittently send a transport stream that is continuously input to a subsequent HDD (Hard Disc Drive) 27. For example, since the transport stream cannot be written when the HDD 27 performs a seek operation, the buffer control circuit 26 temporarily stores the transport stream in a buffer (not shown), and when the write is possible, the input is performed. Write to the HDD 27 at a rate higher than the rate. Thereby, a continuously input transport stream can be recorded on the HDD 27 without interruption. The HDD 27 records a transport stream at a predetermined address in accordance with an instruction from the system controller 10.

  In the present embodiment, IDE (Intelligent Drive Electronics) is used as a protocol for the buffer control circuit 26 and the HDD 27, but the present invention is not limited to this. In this embodiment, the HDD has been described as an example of the recording medium. However, other recording media such as an optical disk, a magneto-optical disk, and a solid-state memory may be used.

  Next, the operation at the time of reproduction of the signal recording / reproducing apparatus 1 will be described with reference to FIG.

  The HDD 27 seeks to a predetermined address according to an instruction from the system controller 10, reads the transport stream, and supplies it to the buffer control circuit 26. The buffer control circuit 26 performs buffer control so that the intermittently input transport stream is continuous, and supplies the transport stream to the multiplexing / demultiplexing circuit 25. The multiplexing / demultiplexing circuit 25 extracts a packetized elementary stream (PES) from the transport stream and supplies it to the MPEG audio / video decoder 28.

  The MPEG audio / video decoder 28 separates the supplied packetized elementary stream into a video elementary stream and an audio elementary stream, and supplies them to an MPEG video decoder and an MPEG audio decoder (not shown) for decoding. As a result, baseband video data and audio data are obtained, and the MPEG audio / video decoder 28 supplies the video data and audio data to the post video signal processing circuit 29 and the switching circuit 32, respectively.

  The post video signal processing circuit 29 performs switching, synthesis, and filter processing between the video data from the MPEG audio / video decoder 28 and the video data from the pre video signal processing circuit 20, and performs on-screen display (OSD). ) Supply video data to 30. The on-screen display 30 generates graphics for screen display and the like, performs processing such as overlapping or partially displaying the video data, and supplies the processed video data to the NTSC encoder 31. The NTSC encoder 31 converts the supplied video data (digital component video data) into a Y / C signal, and then performs D / A conversion to obtain an analog composite video signal and an S video signal.

  On the other hand, the switching circuit 32 selects either the audio data from the MPEG audio / video decoder 28 or the audio data from the audio A / D converter 22 and supplies the selected audio data to the audio D / A converter 33. The D / A converter 33 converts the supplied audio data into an analog audio signal.

  Next, an operation at the time of recording / reproducing a signal inputted / outputted digitally will be described with reference to FIG.

  For example, when recording digital data input from an external IRD (Integrated Receiver Decoder) via a digital interface such as IEEE1394, the digital data is input to the digital interface circuit 24. The digital interface circuit 24 performs processing such as format conversion on the digital data so as to conform to this method, generates a transport stream, and supplies the transport stream to the multiplexing / demultiplexing circuit 25. The multiplexing / demultiplexing circuit 25 further analyzes and generates a control signal and the like, converts it into a transport stream adapted to this system, and supplies it to the buffer control circuit 26. Subsequent processing is the same as described above, and is omitted.

  Also during reproduction, the processing up to the multiplexing / demultiplexing circuit 25 is the same as described above, and is therefore omitted. The multiplexing / demultiplexing circuit 25 analyzes and generates the control signal as necessary, and supplies the transport stream to the digital interface circuit 24. The digital interface circuit 24 performs conversion opposite to that at the time of recording, converts it into digital data suitable for an external IRD, and outputs the digital data. At the same time, separation processing is performed by the multiplexing / demultiplexing circuit 25 and a packetized elementary stream is supplied to the MPEG audio / video decoder 28, whereby an analog video signal and audio signal can be obtained.

  Note that although connection with an IRD has been described in this embodiment mode, connection with an AV device such as a television device or a personal computer is also possible.

  The above is the operation at the time of normal recording / reproducing of the signal recording / reproducing apparatus 1 in the present embodiment. This signal recording / reproducing apparatus 1 restores the transport stream recorded in the HDD 27 to analog video signals and audio signals. Then, when reproducing, the reproduction speed can be changed, that is, variable speed reproduction can be performed. In particular, the signal recording / reproducing apparatus 1 can improve the reproduction quality of sound during variable speed reproduction. Therefore, hereinafter, the operation of the signal recording / reproducing apparatus 1 during variable speed reproduction, specifically, the operation of the MPEG audio / video decoder 28 will be described.

  The internal configuration of the MPEG audio / video decoder 28 is shown in FIG. As shown in FIG. 2, the MPEG audio / video decoder 28 includes a separation circuit 40, an MPEG video decoder 41, an MPEG audio decoder 42, and a thinning circuit 43.

  For example, in the case of double speed variable speed reproduction, since the packetized elementary stream is supplied to the separation circuit 40 at a double supply rate, the separation circuit 40 performs packet processing at twice the processing speed compared to normal reproduction. The elementary stream is separated into a video elementary stream and an audio elementary stream, and the video elementary stream is supplied to the MPEG video decoder 41 and the audio elementary stream is supplied to the MPEG audio decoder 42 at a double supply rate. When the MPEG video decoder 41 does not operate at the double speed, only the portion used for the double speed playback is extracted from the video elementary stream in accordance with an instruction from the system controller 10 (FIG. 1). To supply.

  The MPEG video decoder 41 performs decoding processing on the supplied video elementary stream to generate baseband video data, and outputs the video data suitable for double speed variable speed playback to the post video signal processing circuit 29 (FIG. 1). ). On the other hand, the MPEG audio decoder 42 performs double-speed decoding processing on the supplied audio elementary stream to generate baseband audio data (PCM (Pulse Code Modulation) data), and this audio data is converted into normal audio data. The data is supplied to the thinning circuit 43 at a supply rate twice that at the time of reproduction. The thinning circuit 43 performs a process of thinning the supplied audio data in half, and supplies the audio data after the thinning to the switching circuit 32 (FIG. 1).

  An example of the internal configuration of the thinning circuit 43 is shown in FIG. As shown in FIG. 3, the thinning circuit 43 includes a signal analysis circuit 50, an HPF (High Pass Filter) designating circuit 51, a switching circuit 52, an HPF circuit 53, a PCM data thinning circuit 54, and a crossfade coupling circuit. 55.

  For example, in the case of double speed variable speed reproduction, the audio data (PCM data) is supplied to the signal analysis circuit 50 and the HPF circuit 53 at twice the supply rate as compared with normal reproduction. The signal analysis circuit 50 analyzes the characteristics such as the frequency characteristics and the sound pressure level of the supplied PCM data to derive an optimum HPF characteristic, and supplies the characteristic information to the switching circuit 52. On the other hand, the HPF designation circuit 51 receives designation of the HPF characteristic from the system controller 10 (FIG. 1) and sends it to the switching circuit 52. At this time, the system controller 10 indicates a predetermined characteristic determined based on, for example, an average sound level of television broadcasting, or is selected by a viewer from a plurality of characteristic templates prepared in advance. There is a case where an instruction is given, or a case where a characteristic is indicated based on electronic program guide (EPG) such as news or a music program. The switching circuit 52 selects either the output of the signal analysis circuit 50 or the output of the HPF designation circuit 51 in accordance with an instruction from the system controller 10, and supplies the selected side characteristic information to the HPF circuit 53.

  The HPF circuit 53 performs filtering processing on the PCM data based on the HPF characteristic information supplied from the switching circuit 52, and sends the PCM data obtained by attenuating the sound pressure level on the low frequency side to the PCM data thinning circuit 54. Supply. In the present embodiment, the filtering process is performed on the PCM data in the HPF circuit 53 in this way, thereby reducing noise generated when low-frequency PCM data is supplied and suppressing deterioration in reproduction quality. Details of this point will be described later.

  The PCM data decimation circuit 54 receives PCM data at a double supply rate, and performs decimation processing on the PCM data in units of continuous PCM data having a certain length based on the fundamental frequency of human speech, for example. The PCM data after the thinning process is supplied to the cross-fade coupling circuit 55 at a rate slightly higher than one time. Note that as a means for determining which part of the continuous PCM data is to be separated and combined with which part of the PCM data, a method using the sound pressure level or the fundamental frequency of the PCM data is conceivable. The cross-fade combining circuit 55 performs fade-out processing and fade-in processing on individual cut ends of two supplied continuous PCM data units, combines them into one PCM data, and combines the combined PCM data to 1 The switching circuit 32 (FIG. 1) is supplied at a double supply rate.

  FIG. 4 shows a time axis waveform of PCM data input / output to / from the PCM data thinning circuit 54 and the cross-fade coupling circuit 55 at the time of double speed speed reproduction. 4A shows the input data waveform of the PCM data thinning circuit 54, FIG. 4B shows the output data waveform of the PCM data thinning circuit 54, and FIG. 4C shows the output data of the cross-fade coupling circuit 55. Waveform is shown. The PCM data thinning circuit 54 captures the periodicity of the supplied PCM data, and cuts out the thick line portion of the time axis waveform in FIG. 4A as shown in FIG. Then, the cross-fade combining circuit 55 performs fade-out processing and fade-in processing on the joint surface of the two pieces of cut-out PCM data, and then overlaps a part of the PCM data to combine them as shown in FIG. .

  In the configuration of FIG. 3, the HPF circuit 53 performs the filtering process before performing the thinning process and the cross fade process on the PCM data. That is, the preceding stage of the PCM data thinning circuit 54 and the cross fade coupling circuit 55 is performed. However, the HPF circuit 53 may be provided after the PCM data thinning circuit and the cross-fade coupling circuit.

  FIG. 5 shows an internal configuration of the thinning circuit 43 (FIG. 2) in this case. As shown in FIG. 5, the thinning circuit 43 includes a signal analysis circuit 60, an HPF designation circuit 61, a switching circuit 62, a PCM data thinning circuit 63, a crossfade coupling circuit 64, and an HPF circuit 65.

  For example, in the case of double speed variable speed reproduction, the audio data (PCM data) is supplied to the signal analysis circuit 60 and the PCM data thinning circuit 63 at a supply rate that is twice that of normal reproduction. The signal analysis circuit 60 and the HPF designation circuit 61 supply the HPF characteristic information to the switching circuit 62 in the same manner as described above. The switching circuit 62 outputs the output of the signal analysis circuit 60 in accordance with an instruction from the system controller 10 (FIG. 1). And the output of the HPF designation circuit 61 are selected, and the selected side characteristic information is supplied to the HPF circuit 65.

  The PCM data decimation circuit 63 receives PCM data at twice the supply rate, and performs decimation processing on the PCM data in units of continuous PCM data having a certain length based on the fundamental frequency of human speech, for example. Then, the PCM data after the thinning process is supplied to the crossfade coupling circuit 64 at a rate slightly higher than one time. The cross-fade combining circuit 64 performs fade-out processing and fade-in processing on individual cut ends of two supplied continuous PCM data units, and then combines the combined PCM data into one PCM data. The HPF circuit 65 is supplied at a double supply rate.

  The HPF circuit 65 performs filtering processing on the PCM data based on the HPF characteristic information supplied from the switching circuit 62, and converts the PCM data obtained by attenuating the sound pressure level on the low frequency side into the switching circuit 32 (FIG. 1). ). In this embodiment, even in this case, noise generated when low-frequency PCM data is supplied can be reduced and reproduction quality deterioration can be suppressed. Details of this point will be described later.

  Here, as described above, in this embodiment, noise generated when low-frequency PCM data is supplied is reduced by filtering the PCM data in the HPF circuit 53 or the HPF circuit 65. In addition, it is possible to suppress degradation of reproduction quality. This will be described in detail below.

  FIG. 6 shows time axis waveforms of PCM data input / output to / from the PCM data decimation circuit and cross-fade coupling circuit when PCM data having a frequency lower than that in FIG. 4 is supplied during double speed speed reproduction. 6A shows the input data waveform of the PCM data thinning circuit, FIG. 6B shows the output data waveform of the PCM data thinning circuit, and FIG. 6C shows the output data waveform of the cross-fade coupling circuit. . In FIG. 6, since the fundamental frequency of the PCM data supplied to the PCM data thinning circuit is lower than that in FIG. 4, the time axis waveform of the PCM data output from the cross-fade coupling circuit shown in FIG. It can be seen that

  In order to eliminate this distortion, a method of widening the cut-out interval in the PCM data thinning circuit and expanding the cut-out unit can be considered, but the amount of PCM data to be stored increases accordingly, leading to an increase in the required memory amount. End up. Furthermore, it is difficult to cover all the fundamental frequencies of various kinds of sounds included in television broadcasting and the like. Therefore, in the present embodiment, the HPF circuit 53 or the HPF circuit 65 is provided in the thinning circuit 43 (FIG. 2) in order to reduce distortion generated when the low-frequency PCM data is supplied.

  FIG. 7A shows a spectrogram obtained by extracting waveform distortion generated when low-frequency PCM data is supplied as shown in FIG. 6C and converting it to the frequency axis. FIG. 7A shows the frequency characteristics of the output PCM data at a certain moment when no HPF circuit is provided in the thinning circuit 43 (FIG. 2). FIG. 7B shows the frequency characteristics when the filtering process is performed after the thinning process and the cross fade process as shown in FIG. 5, and the filtering process is performed before the thinning process and the cross fade process as shown in FIG. The frequency characteristics when applied are shown in FIG.

  Since the waveform distortion has an impulsive signal component, noise is added over the entire frequency band as shown in FIG. On the other hand, when the filtering process is performed after the thinning process and the cross-fade process, as shown in FIG. 7B, noise can be reduced with respect to a part of the low frequency, and deterioration of reproduction quality can be suppressed. However, the reduction effect does not work for noise added to the mid-high range. In addition, when filtering processing is performed before thinning processing and cross fading processing, waveform distortion occurs in order to suppress the amplitude of a low-frequency component that is a source of noise in advance, but the step of the waveform becomes small. As shown in FIG. 7C, noise can be greatly reduced, and deterioration of reproduction quality can be suppressed. Therefore, when it is desired to further reduce the noise, it is preferable to perform a filtering process before the thinning process and the cross fade process. However, in this case, since the PCM data is supplied to the HPF circuit at a supply rate that is twice as high as that during normal reproduction, the amount of filtering processing increases.

  Here, the HPF circuit 53 and the HPF circuit 65 perform processing for lowering the sound pressure level in the low frequency range, but several specifications are assumed as frequency characteristics of the HPF. For example, by using a technique for attenuating the sound pressure level in a frequency band lower than the fundamental frequency of human voice, a musical sound signal including a low-frequency component can be obtained without impairing how human voice is heard during variable speed playback. Deterioration of reproduction quality can be suppressed. Also, various specifications are assumed for the attenuation of the sound pressure level. However, if a specific frequency component is deleted extremely, it may be uncomfortable compared to the original sound. It is preferable to keep the attenuation amount of HPF to the extent that it is masked by the sound pressure level of the fundamental tone.

  As described above, according to the signal recording / reproducing apparatus 1 and the method thereof in the present embodiment, the filtering process is performed by the HPF circuit in the former stage or the latter stage where the thinning process is performed on the PCM data for the variable speed reproduction. Therefore, compared to the conventional method, it is possible to reduce noise caused by waveform distortion that occurs when a musical tone signal having a lower frequency component is reproduced while shifting, while maintaining ease of hearing of human voice during variable speed reproduction. Can do. As a result, it is possible to improve the reproduction quality when the original sound signal including various kinds of sounds such as musical instrument performance sounds and natural environment sounds as well as human voices is subjected to variable speed reproduction.

  It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, the HPF circuit is described as being provided inside the thinning circuit. However, when high frequency component regeneration is not required during variable speed regeneration, a BPF (Band Pass) is used instead of the HPF circuit. (Filter) circuit may be provided.

It is a figure which shows schematic structure of the signal recording / reproducing apparatus in this Embodiment. It is a figure which shows the internal structure of the MPEG audio / video decoder in a signal recording / reproducing apparatus. It is a figure which shows an example of the internal structure of the thinning circuit which an MPEG audio / video decoder has. It is a figure which shows the time-axis waveform of the PCM data inputted / outputted to the PCM data thinning circuit and the cross fade coupling circuit which the thinning circuit has at the time of double speed speed reproduction. It is a figure which shows the other example of the internal structure of the thinning circuit which an MPEG audio / video decoder has. FIG. 5 is a diagram illustrating a time axis waveform of PCM data input / output to / from a PCM data thinning circuit and a crossfade coupling circuit included in a thinning circuit when PCM data having a frequency lower than that in FIG. 4 is supplied during double speed speed reproduction. is there. The figure which compares the noise which occurs when low frequency PCM data is supplied at the time of 2 × speed variable speed reproduction with the case where it does not have the HPF circuit and the case where it is provided before or after the thinning circuit and the cross fade coupling circuit is there.

Explanation of symbols

  1 signal recording / reproducing apparatus, 10 system controller, 27 HDD, 28 MPEG audio / video decoder, 40 separation circuit, 41 MPEG video decoder, 42 MPEG audio decoder, 43 decimation circuit, 50 signal analysis circuit, 51 HPF designation circuit, 52 switching Circuit, 53 HPF circuit, 54 PCM data thinning circuit, 55 crossfade coupling circuit, 60 signal analysis circuit, 61 HPF designation circuit, 62 switching circuit, 63 PCM data thinning circuit, 64 crossfade coupling circuit, 65 HPF circuit

Claims (14)

In a signal reproduction device that reads an original sound signal recorded on a recording medium and performs variable speed reproduction in a shorter time than the recording time of the original sound signal,
Thinning means for performing thinning processing according to the reproduction speed on the original sound signal;
Filtering means for performing a filtering process for attenuating a sound pressure level in a frequency band lower than a predetermined frequency with respect to the original sound signal to a predetermined sound pressure level or less before or after the thinning process; A signal reproducing apparatus comprising:   2. The signal reproducing apparatus according to claim 1, wherein the predetermined frequency is a fundamental frequency of a desired signal in the original sound signal.   2. The signal reproducing apparatus according to claim 1, wherein the predetermined frequency can be specified. The original sound signal is a recorded television signal,
4. The signal reproducing apparatus according to claim 3, wherein the predetermined frequency is specified based on electronic program information.   2. The signal reproducing apparatus according to claim 1, wherein the predetermined sound pressure level is a level masked by a fundamental tone of a desired signal in the original sound signal.   2. The signal reproducing apparatus according to claim 1, wherein the predetermined sound pressure level can be specified. The original sound signal is a recorded television signal,
7. The signal reproducing apparatus according to claim 6, wherein the predetermined sound pressure level is designated based on electronic program information. In a signal reproduction method for reading an original sound signal recorded on a recording medium and performing variable speed reproduction in a shorter time than a recording time of the original sound signal,
A thinning step for performing a thinning process according to the reproduction speed on the original sound signal;
A filtering step of performing a filtering process for attenuating a sound pressure level in a frequency band lower than a predetermined frequency with respect to the original sound signal to be equal to or lower than a predetermined sound pressure level before or after the thinning step; A signal reproduction method comprising:   9. The signal reproduction method according to claim 8, wherein the predetermined frequency is a fundamental frequency of a desired signal in the original sound signal.   9. The signal reproduction method according to claim 8, wherein the predetermined frequency can be specified. The original sound signal is a recorded television signal,
11. The signal reproduction method according to claim 10, wherein the predetermined frequency is specified based on electronic program information.   9. The signal reproduction method according to claim 8, wherein the predetermined sound pressure level is a level masked by a fundamental tone of a desired signal in the original sound signal.   9. The signal reproduction method according to claim 8, wherein the predetermined sound pressure level can be designated. The original sound signal is a recorded television signal,
14. The signal reproducing method according to claim 13, wherein the predetermined sound pressure level is designated based on electronic program information.

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