Hi Dave
Den 17.02.2023 18:47, skrev Dave Rice:
Hi Terje,
On Feb 17, 2023, at 11:52 AM, Terje J. Hanssen<terjejhans...@gmail.com> wrote:
I ask here for ffmpeg feedback on two capture setups from video tape playback
to 422 ffv1.mkv in realtime.
Setup 1) HDV playback/HDMI out -> HDMI-USB3/ms2130 capture -> ffmpeg/v4l2 ->
422 FHD FFV1/MKV
According to S.Mullen's handbook for the camcorder (FX7E here):
According to Sony, the EIP works at 1920x1080 in a 4:2:2 colorspace.
V1 and FX7 provide an HDMI output port that carries uncompressed
4:2:2, 8-bit, digital video plus dual-channel PCM, 16-bit, 48kHz
audio. If you are playing a 1080i50 HDV tape: the 4:2:0 MPEG-2 is
decoded and chroma up-scaled to a 4:2:2. The HDMI chip downscales
1440 to 1280 while it up-scales 540 to 720. The result is 720p50
output via HDMI.
A preliminary test with FX7 camera (not HDV 1080i/MP2 tape playback) and
another ms2109 capture card, supported 422 FHD 1920x1080p at just 5 fps using
this command line:
ffmpeg -hide_banner -f alsa -ac 2 -i hw:CARD=MS2109,DEV=0 -f v4l2
-framerate 25 -video_size 1920x1080 -i /dev/video0 -codec:v ffv1
-level 3 -codec:a pcm_s16le -f matroska video-out_ffv1.mkv
Have you considered avoiding HDMI? Here you’re changing the resolution and
colorspace and audio compression characteristics to include HDMI in the middle
of the process. If you have a firewire cable you could transfer the m2ts stream
from the tape into ffmpeg as use a stream copy rather than a realtime encoding.
Actually my plan was to first transfer the hdv.m2t files from tape
playback via firewire to a stand-alone Datavideo DN-300 DV & HDV HDD
recorder, which I've used a lot previously to digitize analog S-video
and record as DV files. Afterwards I mounted DN-300 via firewire to my
Linux workstation.
But unhappily, ten years old and unsupported hardware seems to just die,
and DN-300 doesn't longer initialize or recognize its HDD during power on.
Currently my HDV camcorder is on service, so I ask: Is it possible to
transfer/grab HDV files via Firewire to ffmpeg? (I have already
libiec61883, libraw1394, libavc1394 installed on my Leap). If so, a
command example or guide to start with would be welcome.
So to HDMI. My preliminar test above was using the camera EIP only, so
possibly there was no video change just in this case. I think I read
somewhere that the camcorder/hardware that compressed and downscaled a
video for storage (here to mpeg-2 hdv on dv tape), probably would do the
best job back again, typical from 4:2:0 to 4:2:2 color subsampling.
The HDMI-USB ms2130 capture card (ordered) should according to its specs
support YUY2, which seems to be 8-bit 422 color precision.
At least for S-video conversion and capture to DV with 4:2:0 color
subsampling, this HDMI way hopefully can give give som better color
reproduction.
The S-video to HDMI converter unhappily has no definitiv specification.
In general my impression have always been that DV playback has some
lesser (darker) colors than the corresponding source S-video tape playback.
Setup 2) PAL S-video playback -> TBC -> ADC/HDMI adapter -> HDMI-USB3/ms2130 capture
-> ffmpeg/v4l2 -> 422 FFV1/MKV
The PAL S-video/AFM HiFi playback can be
* Hi8 tape playback/S-video out from a Sony TR2000E camcorder or a
S880E Hi8 deck
* S-VHS playback from a Panasonic NV-HS1000 S-VHS deck
A preliminary, fictive test trying the FX7 camera to HDMI instead, managed 422
video at 720x576 and 25 fps using this command line
ffmpeg -hide_banner -f alsa -ac 2 -i hw:CARD=MS2109,DEV=0 -f v4l2
-framerate 25 -video_size 720x576 -i /dev/video0 -codec:v ffv1
-level 3 -codec:a pcm_s16le -f matroska video-out_ffv1.mkv
I am somewhat unsure if the above are optimal ffmpeg codes and should like to
get clarified what input/output format definitions (standards PAL, resolution,
colors, framerates etc) that are neccesary and recommended, when here are both
a source tape playback device and video out via HDMI and ADC or HDMI-USB card?
I’d suggest adding more of the audiovisual characteristics if your input isn’t
providing them.
How do I possibly know or verify if the input does or doesn't provide
these caracteristics?
Does ffmpeg/v4l2 recognize the camcorder player output, or just read
from the ADC and/or the HDMI-USB3 capture card?
For instance, for an S-video PAL source I think you could add:
-color_range mpeg
Possibly I misunderstand something here, but why "mpeg" color_range?
-color_primaries bt470bg
-color_trc bt709
-colorspace bt470bg
If ffmpeg interprets the input as non-interlaced when it is, you could add:
-vf setfield=tff
Also if ffmpeg interprets the input without an aspect ratio you may want to set
it, else you’ll get a 1/1 SAR with your command.
Earlier playback has showed a bit flickering at the top and bottom horizontal
line of the S-video 720x576. Possibly these can be cropped away with ffmpeg
crop filter, or optional map or crop the whole 4:3 video image to 16:9.
Suggestions?
I wonder if filter map and crop does the same, that is cut off top and
bottom of a 4:3 SD image to make it 16:9 wide SD, which can be upscaled
to fullscreen during playback on typical a 16:9 HDTV?
I thought to apply a command like this (Pad 4:3 into 16:9) which is
aimed to "Transform a video file with 4:3 aspect ratio into a video file
with 16:9 aspect ration by correct pillar-boxing":
https://avpres.net/FFmpeg/4-3_16-9
ffmpeg \
-i input_file \
-filter:v "pad=ih*16/9:ih:(ow-iw)/2:(oh-ih)/2" \
-c:a copy \
output_file
That may just be head switching from the original videotape. You may be able to
control that with tracking or head alignment in the unit if that’s adjustable.
Yes, I know it happened after a camcorder service, and the Hi8 deck is
also another but better player than recorded on.
By the way, I don't take the risk now to adjust the head.
Otherwise if you’re using Matroska you could consider using the PixelCrop*
elements to store the intended display aperture for the video, while still
storing the entire frame.
Dave
Thank you for good advices !
Terje
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