Dv

Page dedicated to extraction and conversion of DV tape, as used in digital camcorder.

Capture

DV tape capture requires a PC with a firewire (IEEE 1394) port.

• Check installation:

# Check firewire hardware
lspci | grep -i firewire
# 37:09.0 FireWire (IEEE 1394): LSI Corporation FW322/323 [TrueFire] 1394a Controller (rev 70)

# Check kernel modules are loaded
lsmod | grep firewire
# firewire_ohci          40960  0
# firewire_core          65536  7 firewire_ohci
# crc_itu_t              16384  1 firewire_core

# Install some tools
sudo apt install dvgrab gscanbus
# sudo apt install libraw1394-11   # optional

# See if camera is detected
sudo gscanbus

# Add current users to 'video' (must logout / login) to allow access to /dev/fw
sudo usermod -aG video $USER

• Grab the DV tape

dvgrab -format=dv2 -rewind -autosplit=14400 -srt -size 0 myvideo-
# -format=dv2: recommended format. Alternative: raw (extension .dv)
# -rewing: rewing before capture
# -size 0: Do not split files based on size
# -autosplit=14400: Split file if there is a gap bigger than 4h.
# -srt: generate subtitles with recording date and time.

Tips / How-to

Recover recording datecode

Raw DV files contain recording datecode information (date + time). There are several methods to recover that information and make subtitle files with them (*.srt).

Capture the DV with dvgrab and -srt option.

• See Capture section.

Extract the information from a RAW DV file.

• This only works if the DV was extracted in raw DV format.
• mediainfo must return something like:

mediainfo test001.dv
# General
# Complete name                            : test001.dv
# Format                                   : DV
# Commercial name                          : DVCAM
# File size                                : 1.01 GiB
# Duration                                 : 5 min 0 s
# Overall bit rate mode                    : Constant
# Overall bit rate                         : 28.8 Mb/s
# Recorded date                            : 2003-10-30 19:57:45.000
# 
# Video
# Format                                   : DV
# Commercial name                          : DVCAM

• In that case, generate again the *.srt files with dvgrab, which accepts directly DV raw files.

dvgrab -input test001.dv -f raw -t -srt -size 0 test001-srt

Extract information from an AVI DV file

• If the file is NOT in raw DV format but in AVI, the easiest is to use a Windows application called dvdate (DVdate on videohelp.com).
• Open folder containing the AVI file.
• Go to Inlay, and select Create a srt file with subtitles.

Convert AVI to RAW DV file

• This method is much less efficient since it means duplicating the file again.
• Enosoft DV Processor (Windows, Enosoft-DV-Processor on videohelp.com) can convert the AVI file into a RAW DV that can then be processed with dvgrab
• Note that currently ffmpeg does not preserve the recording datecode metadata, and so cannot be used for the conversion.

Benchmarks

# Source: dv1_tlg_to_jan_2005
 size  | enc fps  | format
-------|----------|----------------------------------------------------------------------
14543M |          | DV
 1489M | 64.1 fps | x264 slow-20-high-3.1
 2082M |  9.4 fps | x265 slow-18-auto-auto
 1815M | 21.0 fps | x265 medium-18-auto-auto
 1215M | 24.1 fps | x265 medium-20-auto-auto
  917M | 27.35 fps| x265 medium-20-auto-auto + strong-intra-smoothing=0:rect=0:aq-mode=1

• We choose x265-medium-20-auto-auto.

• Better than the x265-medium-20 with extra options (extra noise).
• No significant differences compared to best quality file (x265 slow).