The purpose of synchronous recording and recording work in interrogation place is to fix audio-visual evidence, so synchronous recording and recording work should be carried out around audio-visual evidence. Synchronous audio and video recordings are audio-visual materials used in criminal proceedings, which are based on audio-visual tapes, video tapes, CD ROMs, etc. The synchronous recording and video recording work of procuratorial organs not only extracts evidence but also fixes evidence. Then, is this audio-visual material accepted in court and can it stand the examination of material evidence institutions?

The formation of evidence chain of synchronous recording and recording should pay attention to the following three points:

1. The recording equipment shall be easy to identify and its content shall not be changed.
How to identify products? First, look at the first storage medium of the device. With the wide application of computer technology, the simple PC + software mode and hard disk video recorder mode for synchronous recording and recording equipment have emerged one after another, they mainly use hard disk as the first storage medium of original evidence. Because of its many subsidiary functions, it is favored by some grassroots procuratorates. However, because its first storage medium is hard disk, which is characterized by strong erasure and repetition, the video content produced by it is very easy to be modified, which is highly concerned by criminal suspects, judges and lawyers. If we use the method of caching in the hard disk or the internal memory of PC first, and then recording the disc, it is easy to generate objections. Therefore, whether the synchronous recording and recording are stored in the hard disk or memory first and then recorded should be based on whether the content stored in the hard disk can be identified by physical evidence. At the same time, according to the requirements of physical evidence, the hard disk with original evidence should also be sealed independently.

Therefore, it is recommended to use the synchronous direct recording device with the function of digital encryption of disc track and the method of synchronous storage of independent recording on hard disk as the recording and recording device. Because the disc itself has the physical characteristics that can not be edited by people, it can be used as the first original evidence, and the hard disk is only used as the synchronous independent backup, so as to ensure the authenticity of the original disc as the first storage medium of evidence The determination of sex and identity can prevent the disc from being transferred, and at the same time avoid the suspicion of modification and the loss of audio-visual evidence status in the process of asynchronous disc transfer.

When the audio-visual evidence is synchronously engraved with the fixed evidence, the direct fixed equipment shall adopt the embedded data random encryption system to encrypt the video track of the original evidence disc point by point, so as to prevent the original disc from being replaced artificially. This encryption system cannot be set artificially. The physical evidence identification agency can identify and verify the encryption and authentication information code in its disc track by using the disc test equipment. The original disc can also be played or copied in any media player. The copied disc does not have the original disc encryption and authentication information code. The criminal suspect signs the audio and video information recorded in the original disc according to this English digital mixed code The sample can ensure fairness and justice, and also facilitate the identification of the same machine and disk by the material evidence identification agency in case of dispute.

Our company believes that the synchronous recording and video equipment should form the following fixed chain of evidence: time code + environment information synchronization + disc direct cutting + disc track digital encryption + disc electronic video Number + dual disc synchronous real-time fixation + independent hard disk backup. It should be noted that at present, some devices can burn discs on the surface, but actually adopt the asynchronous delayed hard disk transcribing mode. The evidence of this fixed mode will also be questioned. The material evidence appraisal organization also does not accept this kind of disputed evidence. Therefore, when selecting the equipment, we should also consider whether the equipment has passed the demonstration of the national authoritative material evidence appraisal institution or the scientific and technological appraisal of the Ministry or above, and has the production license of audio-visual evidence products issued by the relevant functional institutions of the state, so as to avoid the use of temporary equipment and prevent the waste of funds.

2. Strictly follow relevant technical specifications and work flow.
The problem of audio-visual materials being falsified and tampered has been paid more and more attention by the experts in the field of physical evidence identification and trial. The Department of physical evidence identification has formulated strict testing procedures for the disputed audio-visual evidence. In addition to the sound pattern synchronization and frame field identification of the audio-visual evidence storage medium and its content, it also pays special attention to the more strict review of the recording and video equipment that fixes its audio-visual materials, such as the verification of the fixed equipment of the evidence, so as to identify the over storage of the audio-visual evidence in the fixed storage to the final media Is there any suspicion of tampering in the process. Therefore, it is recommended to avoid using the PC type with programming function or the device that relies on the transfer between the storage medium and the storage medium to fix the evidence.

3. Identification and inspection.
The identification of the material evidence identification department should first test the scientificity, rationality, preciseness, synchronicity and immutability of the synchronous recording and video equipment and storage medium of the fixed audio-visual materials; secondly, test the credibility of the original CD of the fixed audio-visual materials.

In the process of specific collection and fixation of audio-visual evidence, audio-visual evidence also needs to be tested; as long as the live interrogation process recorded in the form of video during the interrogation is broadcast in court, the defendant's excuses for confession will not be broken. If the fixed method is improper or the audio-visual evidence provided has no test conditions, the suspect will question the originality of the audio-visual evidence.

In a word, audio-visual materials are easy to be counterfeited and used as evidence only after being examined by legal procedures. With the comprehensive development of synchronous recording and video work, we should carefully understand the connotation of synchronous recording and video work when selecting equipment and methods, especially from the perspective of physical evidence, to avoid repeated construction. The procuratorial organ should pay attention to the evidence in the synchronous recording and video recording, and regard whether the court accepts the evidence as the foothold of the synchronous recording and video recording work.