T 0233/05 09-01-2009

1. Admissibility

The appeal is admissible.

2. Document E1

E1 concerns a video recorder and playback device allowing a video signal to be simultaneously recorded and, after a variable time delay, played back; see abstract, first sentence. E1 discloses various technical approaches to realizing such a device. The first embodiment is "sequential" in that the video signal is recorded on and played back from a sequential medium, such as video tape. The second embodiment is described as "random access" in that the video signal is digitised and stored in a random access memory (see figure 3), such as a magnetic disk. According to column 6, lines 50 to 58, and figure 3, an analogue video signal is digitized, compressed and stored in a random access memory. Data from the memory is then subsequently decompressed and converted back into analogue signals. Recording and playback may be done essentially simultaneously by multiplexing writing to and reading from the memory; see column 6, lines 36 to 38. This can be achieved by realizing the random access memory as two memory types. A solid state buffer holds one second's worth of data until compression has been performed, the compressed data then being stored on a hard disk "as employed in personal computers"; see column 7, lines 61 to 68.

The board understands the references in E1 to recording and playback occurring essentially simultaneously by multiplexing writing to and reading from the memory (see column 6, lines 36 to 38) as concurrently recording and reproducing a broadcast program on a conventional TV display (abstract; column 6, lines 32 to 36). The signal sampler 51 and analogue to digital converter 52 shown in figure 3 constitute input means inputting a video signal. Figure 3 also shows compression means (see data compressor 57) for compressing an amount of information of the input video signal so as to output a compressed video signal and corresponding decoding means (see decompressor 59) for decompressing an amount of information of the decompressed video signal for reproduction.

Although E1 only mentions the use of a buffer when writing to the hard disk (see column 7, lines 61 to 68), the board takes the view that it was implicit to the skilled person interpreting figure 3 in the light of the references to multiplexed recording and playback (see column 6, lines 36 to 38, and column 7, lines 66 to 68) that in E1 recording and playback are mirror images of one another, playback merely reversing the steps taken when recording. Hence the skilled person would have understood that E1 implies the use of a playback buffer corresponding to the recording buffer. The skilled person would also have been aware that the recording and playback buffers used to multiplex recording and playback operations must allow data to be written to and read from the hard disk faster than it arrives from the data compressor 57 and is passed to the decompressor 59 shown in figure 3. This must be so because the broadcast analogue video signal is input at a constant frame rate and a conventional hard disk could not be read out during a writing operation. Thus, to avoid the recording buffer overflowing while the disk is being read and to avoid the playback buffer emptying while the disk is being written to, data transfer to and from the disk must be faster than the continuous data transfer from the compressor (for example an MPEG bit stream) to the recording buffer. Since data is read out of the recording buffer faster than it is read in, the recording buffer constitutes time compression means for compressing an amount of time of the compressed video signal along a time axis so as to obtain a compressed video writing signal. Likewise, since data is read into the playback buffer faster than it is read out, the playback buffer constitutes time decompression means for decompressing an amount of time of the compressed video reading signal along the time axis so as to obtain a decompressed video signal for reproduction. Given that recording to and playback from the hard disk in E1 occurs in a multiplexed manner, it was furthermore implicit to the skilled person that in E1 control means are present for controlling the writing means and the reading means such that a period during which the compressed video writing signal is written onto the hard disk apparatus does not overlap with a period during which the compressed video reading signal is read from the hard disk apparatus.

Since E1 refers to the hard disk being "as employed in a personal computer" (see column 7, lines 61 to 66), it was also implicit for the skilled person that the hard disk in E1 comprises writing means for writing the compressed video writing signal onto a plurality of different portions of the hard disk apparatus via a magnetic head and reading means for reading an arbitrary compressed video writing signal, which was previously written onto the plurality of different portions of the hard disk apparatus, from the hard disk apparatus via the magnetic head to obtain a compressed video reading signal.

The appellant has argued that the term in the claims "successive" limits each of said portions to contiguous sectors of the hard disk. The board does not agree. The term "successive" only occurs in the patent description in paragraph [0027] in the statement that "In this example, since each of a plurality of successive sectors corresponds to one second, sector addresses are indicated every other second in Figure 3". In this context the board understands "successive" sectors to mean sectors following each other in time, rather than necessarily following each other spatially in the sense of contiguity. Hence the board takes the view that E1 discloses writing onto portions of the hard disk having successive sectors as specified in present claim 1.

The board finds that it was common general knowledge and thus implicit for the skilled person that the hard disk has a write seek time for moving the magnetic head to write onto the hard disk apparatus and a corresponding read seek time for moving the magnetic head to read from the hard disk apparatus.

In order that the recording buffer in E1 does not overflow whilst the disk is being read and the playback buffer does not empty while the disk is being written to, the skilled person would have understood that the period for the compressed video signal which is output from the compression means (then buffered and written onto the disk as a plurality of blocks of length equivalent to one second of video frames; see E1, column 7, lines 38 to 50) has to be longer than a time T, where the time T is defined as a sum of the seek time required for moving the magnetic head to write the compressed video writing signal onto the hard disk apparatus, the time required for writing the compressed video writing signal onto the hard disk apparatus, the seek time required for moving the magnetic head to read the compressed video reading signal from the hard disk apparatus, and the time required for reading the compressed video reading signal from the hard disk apparatus.

3. Inventive step, Article 56 EPC 1973

3.1 The main request

In the light of the above analysis, the subject-matter of claim 1 differs from the disclosure of E1 in that:

(a) the compression means compress units of M frames to yield compressed video and, correspondingly, the decoding means decompress signals to yield units of M frames;

(b) the time compression means compress a unit of N*M frames and, correspondingly, the time decompression means decompress a unit of N*M frames and

(c) N*M frames are written onto L successive sectors of the disk,

(d) where L, M and N each is an integer greater than or equal to 1.

It is common ground between the parties, and the board agrees, that at the priority date the MPEG standard was the best known procedure for compressing and decompressing video signals, and therefore the obvious choice for the skilled person implementing the device known from E1. In doing so the skilled person would have been aware of the frame format of the usual TV standards, for example NTSC corresponding to 30 frames per second. The board takes the view that the skilled person would have designed the compression and decoding means (feature "a" above) and time compression and time decompression means (feature "b" above) to operate on a group of pictures (GOP) of 15 frames as a matter of usual design, NTSC corresponding to 2 GOPs of 15 frames per second. This would correspond to the choice of M=15 and N=2 (see paragraph [0028] of the patent specification), these all being integer values; see feature "d" above. The writing of the resulting compressed video writing signal of N*M frames onto L successive sectors of the hard disk (feature "c" above) thus constitutes a straightforward implementation of writing a plurality of blocks of length equivalent to one second of video frames as taught in E1, column 7, lines 38 to 50. The skilled person would have been aware that a second of video compressed in this way amounts to several megabytes. Since the storage capacity of a PC hard disk sector was at most 2 kilobytes, and the appellant has not proved that it was usual to access merely part of a sector, the board finds that the skilled person would have chosen an integer value of L greater than 1 as a matter of routine; see feature "d" above. Hence the skilled person would have selected values for each of L, M and N which were greater than 1 in an obvious manner, thus arriving at the subject-matter of claim 1 according to the main request without inventive step.

3.2 The first auxiliary request

Since claim 1 differs from that of the main request in that L, M and N are further constrained to all be greater than one, the reasoning for the main request also applies to claim 1 according to the first auxiliary request.

3.3 Conclusion on inventive step

The subject-matter of claim 1 according to both the main and the first auxiliary request is not considered to involve an inventive step, Article 56 EPC 1973.

4. The second auxiliary request, admissibility

The second auxiliary request, made in the oral proceedings before the board, relates to amendments to claim 1. These amendments constitute an amendment to the appellant's case after oral proceedings have been arranged. According to Article 13(3) RPBA (see OJ EPO 2007, 536), such amendments to a party's case "shall not be admitted if they raise issues which the Board or the other party or parties cannot reasonably be expected to deal with without adjournment of the oral proceedings".

Article 13 RPBA reflects both the right to be heard (Article 113 EPC 1973) and the discretionary power of a board to disregard facts or evidence which were not submitted in due time (Article 114(2) EPC 1973), both as to the substance and, where applicable, the admissibility of an amendment. This is particularly true if such amendments are made at a very late stage, as is the case after oral proceedings have been arranged (Article 13(3) RPBA).

The appellant has argued that the amendments were made in reaction to objections under Article 123(2) EPC raised by the board in the annex to the summons. It seems to the board that the respondent's inability to deal with the new request stems largely from the appellant's decision to wait until the oral proceedings before filing the new request. The appellant has argued that too little time was available after the summons to oral proceedings to prepare a submission. The board however notes that the appellant did indeed file a detailed response dated 9 December 2008 to the summons, so it seems that adequate time was indeed available despite the Christmas holidays. Moreover the appellant has not disputed that the date set for the oral proceedings in the summons complied with Rule 71(1) EPC 1973. The board consequently takes the view that the appellant could have filed the second auxiliary request earlier, with his response to the summons to oral proceedings. Had he done so then the respondent could have decided to attend the oral proceedings or to file written comments. By choosing to wait until the oral proceedings to file the new request, had it been admitted, the appellant would have taken the respondent by surprise and put the board in a position where it could not deal with it without adjournment of the oral proceedings. Under these circumstances Article 13(3) RPBA requires that the amendments to the appellant's case not be admitted.

The board consequently decided not to admit the second auxiliary request.

5. Conclusion

Since neither of the appellant's main or first auxiliary requests is allowable and the second auxiliary request is not admitted, the appealed decision cannot be set aside.