Hello
I have a raw audio file extracted from a CCTV DVR. The DVR uses a Techwell TW2865 video / audio codec. The datasheet states "PCM 8/16 bit and u-Law/A-Law 8bit for audio word length".
The audio stream has what looks like an 8-byte header at the start of every frame. Each frame is 248 bytes in size (including the header). The header begins with the byte values "00 01 7A 00".
Using Sox I am able to play the file with the following (guessed) command line:-
However the playback is swamped with noise; I can barely hear the speech in the recording.
I have tried experimenting with various options in Sox and also Audacity (import>raw) but I get the same results.
I have stripped the 8-byte headers from each frame but I get the same results.
Has anyone seen this type of audio stream before? Does anyone have suggestions on how to play the file correctly?
The file (with and without the 8-byte frame headers) can be downloaded from here:-
Raw audio with headers
Raw audio without headers
Thanks
Robin
I have a raw audio file extracted from a CCTV DVR. The DVR uses a Techwell TW2865 video / audio codec. The datasheet states "PCM 8/16 bit and u-Law/A-Law 8bit for audio word length".
The audio stream has what looks like an 8-byte header at the start of every frame. Each frame is 248 bytes in size (including the header). The header begins with the byte values "00 01 7A 00".
Using Sox I am able to play the file with the following (guessed) command line:-
CODE
sox -r 8k -e a-law audio.raw -d
However the playback is swamped with noise; I can barely hear the speech in the recording.
I have tried experimenting with various options in Sox and also Audacity (import>raw) but I get the same results.
I have stripped the 8-byte headers from each frame but I get the same results.
Has anyone seen this type of audio stream before? Does anyone have suggestions on how to play the file correctly?
The file (with and without the 8-byte frame headers) can be downloaded from here:-
Raw audio with headers
Raw audio without headers
Thanks
Robin