If the video is of a meeting, debate or speech then it will save the lawyer a lot of time if you can make a transcript saving the transcript as a PDF file named - e.g.
2011-03-24 Transcript of Recording of meeting at Africa House (made on 16 June 2015).pdf
(The date at the beginning of the file name is the date the recording was made, not the date you made the transcript).
When you send the transcript to a lawyer, if there is an important part of the recording which needs to be heard or seen – e.g. a particular tone of voice used at some point, or a gesture made, which it is necessary to see/hear to appreciate the full impact and meaning of what is said – then, when sending the recording, you should indicate (by reference to the transcript) which particular parts should be viewed.
Transcribing a lengthy recording can take a considerable amount of time. It is only necessary to transcribe the relevant parts. Sometimes the whole of the recording is relevant but if, for example, there is a conversation between people on friendly terms it may be that out of an hour’s conversation, most of what is said is general friendly conversation about matters which are irrelevant to what the current dispute is about, and only 5 minutes is a discussion of what is relevant (e.g. a discussion of a business transaction which is now in dispute). In this case the transcript can simply summarise in a few words the general conversation (e.g. “general conversation about the parties’ children and how the English cricket team is doing”) and only set out verbatim the 5 minute relevant conversation.
If the recording is of a formal meeting at which minutes are being made by a secretary and if, having heard the recording, you believe the minutes are an accurate summary of what was said (i.e. nothing significant has been missed out and the minutes have not been “slanted” in a way which does not do justice to what was said) then in that case it is not necessary to make a transcript. You should let your lawyer know that there was a recording and that, having seen it, you are satisfied that the minutes are fair.
If the video is not of a meeting debate, speach etc. but is a view of something happening at a site or just of the site itself - perhaps with people commenting but with comments which are not really suitable for transcribing because they cannot really be appreciated without seeing what is happening when the comments are being made, you should send the video with a brief summary of what it contains, which parts (identified by how many minutes and seconds into the recording) in particular you think the lawyer should look at, and any comments on particular parts such as "shows large flow of water being discharged onto the land from the neighbouring property – note that the resulting flood can be seen to extend up two doorsteps".