GB2405741A

GB2405741A - DVD Recorder for simultaneous recording of multiple audio and video signals

Info

Publication number: GB2405741A
Application number: GB0320811A
Authority: GB
Inventors: David Horn; Jeff Horn; Stuart Horn; Peter Scheiwiller
Original assignee: DAVID HORN COMM Ltd
Current assignee: DAVID HORN COMM Ltd
Priority date: 2003-09-05
Filing date: 2003-09-05
Publication date: 2005-03-09
Also published as: GB0320811D0

Abstract

A device for recording two or more video and audio signals onto recordable DVD media contemporaneously with the events to be recorded (i.e. 'on the fly') to make use of the multiple camera angle facilities of the DVD-Video format. MPEG2 data steams from two or more hardware MPEG2 encoders are re-organised in real time prior to recording by means of hardware or software implementation to create the data structures required for a multi-camera angle DVD recording. In addition, for applications where interview material is recorded for evidence in judicial proceedings the MPEG2 data streams can be analysed during this re-organisation to ensure that an appropriate signal is connected to the video or audio inputs, thus giving a confidence indication that the material has been successfully recorded.

Description

240574 1 DVD RECORDER FOR SIMULTANEOUS RECORDjNG OF MULTIPLE AUDIO AND

VIDEO

SIGNALS

This Invention relates to the simultaneous recording of multiple video and audio signals onto recordable DVD media, particularly, but not restricted to the recording of interviews for use as evidence In judicial proceedings Increasingly there is a requirement to make video recordings of police and other interviews for use as evidence In judicial proceedings. For this purpose two or more simultaneous camera views need to be recorded along with two or more audio channels onto a single DVD disc.

It is well known that DVD physical media specifications (i.e. ECMA-267, 268,274,279) and the DVD-Video application specification (i.e. DVD Forum Book B) allows certain scenes to be recorded with multiple camera angles and sound tracks. However current DVD based video recorders do not allow more than one video signal to be recorded to DVD media 'on the fly' (i.e. contemporaneously with the events being recorded) Instead, to create a DVD with multiple camera angles, compatible with most standalone DVD players ad-hoc data processing has to be performed, usually buffering the data to a hard disk drive before wntng to the recordable DVD media. This means that recording cannot be completed until long after the events have taken place. This makes current DVD recorders unsuitable for recording Interview evidence where two or more independent camera views are required.

According to the present invention there is provided a DVD recorder capable of recording two or more video signals along with two or more audio signals onto recordable DVD media contemporaneously with the events being recorded (i.e. 'on the fly') to make use of the multiple camera angle facilities of the DVD-Vdeo format The required data structures for a multiple camera angle DVD recording are created in real time from the incoming data streams by means of software or hardware implementation immediately prior to recording onto the DVD media. Thereby recording a DVD compatible with most stand-alone DVD players.

Optionally, in addition to creating the appropriate data structures for recording, the Incoming video and audio data streams are analysed to establish that there is in fact a valid Input signal connected This is to give a confidence Indication that the final DVD recording will contain all the Information required for presentation as evidence.

Two specific embodiments of a two channel video and audio DVD recorder capable of writing to DVD recordable media 'on the fly' will now be described.

1) The recorder is based on an IBM Compatible PC (Personal Computer), with PCI (Peripheral Component Interconnection) expansion bus. Two video capture cards with hardware MPEG2 encoders plug into the PCI expansion bus. The video capture cards each make available to the PCI bus a standard MPEG2 (IS013818-3: 1998) program stream (PS), transport stream (TS) or packetsed elementary I stream (PES) Software running on the PC takes the two MPEG2 data streams and re-arranges the data Into Interleaved Video Object Unit (VOBU) data structures as required by the DVD-Video standard for multiple camera angle DVD. In addition the software examines the two MPEG data streams to determine whether a video or audio signal is connected to the appropriate input. If there is no appropriate input signal a visible warning is given via a front panel LED. The reorganised data stream is then passed to packet writing software to allow incremental writing to DVD+RW recordable media. The DVD drive is capable of wntng data at least at twice the normal DVD-Video data rate so as to be able to keep with up with the data rate of the reorganised data stream, which has been assembled from the two initial MPEG2 data streams At the same time a count of the number of VOBUs and their location on the disk is updated When recording is completed the VOBU count and location data is used to update the DVD IFO data structure. This data structure is written to the DVD media by the packet writing software, replacing a dummy data structure which was written to the DVD media at the start of recording. The DVD media is then tnalsed to complete the recording.

2) The recorder is substantially as described above but records onto DVDR or DVD+R recordable media Instead of writing a dummy IFO data structure at the beginning of recording and then replacing it with a data structure representing the actual location and number of VOBU data structures written to the DVD media, a definitive IFO data structure is written to the DVD media at the start of recording The interleaved VOBU data structures are then assembled from the two MPEG2 data streams and written to the DVD media so as to match the IFO data structure already recorded on the DVD.

Claims

1) A DVD recorder capable of recording two or more video signals along with two or more audio signals / onto recordable DVD media contemporaneously with the events being recorded (i.e. 'on the fly') to make I use of the multiple camera angle facilities of the DVD-Video format. I 2) A DVD recorder as claimed in Claim 1, wherein the required data structures for a multiple camera angle DVD recording are created in real time from the incoming data streams by means of software or hardware implementation immediately prior to recording onto the DVD media.

3) A DVD recorder as claimed in Claim 1 or Claim 2 which makes a DVD recording compatible with most stand-alone DVD players I 4) A DVD recorder as claimed in any preceding claim, wherein the incoming video and audio data streams are analysed to establish that there is in fact a valid input signal connected.

5) A DVD recorder substantially as herein described.