[Cin] Is SD and HD 422 Video Capture obtainable with V4L(2)?
Terje J. Hanssen
terjejhanssen at gmail.com
Sun Dec 19 00:25:29 CET 2021
Den 18.12.2021 04:35, skrev Andrew Randrianasulu:
>
>
> On Saturday, December 18, 2021, Terje J. Hanssen
> <terjejhanssen at gmail.com <mailto:terjejhanssen at gmail.com>> wrote:
>
>
>
> Den 17.12.2021 22:49, skrev Andrew Randrianasulu:
>
>
>
> On Saturday, December 18, 2021, Terje J. Hanssen via Cin
> <cin at lists.cinelerra-gg.org
> <mailto:cin at lists.cinelerra-gg.org>
> <mailto:cin at lists.cinelerra-gg.org
> <mailto:cin at lists.cinelerra-gg.org>>> wrote:
>
>
>
> Den 17.12.2021 15:00, skrev Terje J. Hanssen:
>
>
> Den 17.12.2021 04:58, skrev Andrew Randrianasulu:
>
>
>
> On Friday, December 17, 2021, Terje J. Hanssen
> <terjejhanssen at gmail.com
> <mailto:terjejhanssen at gmail.com>
> <mailto:terjejhanssen at gmail.com <mailto:terjejhanssen at gmail.com>>
> <mailto:terjejhanssen at gmail.com
> <mailto:terjejhanssen at gmail.com>
> <mailto:terjejhanssen at gmail.com
> <mailto:terjejhanssen at gmail.com>>>> wrote:
>
> [......]
>
> ===============
>
> I-frame-only 50 Megabit MPEG-2 or comparable
> DV50 in
> 4:2:2 as
> high-end, "visually lossless" intermediate
> format for
> archival and
> suited for editing?
>
> -----------------
>
> Regarding DV50, FFMpeg has a friendly "target
> dv50"
> support
> (similar as "target DVD"). So to get a first
> look on a
> DV50 test
> file, I simply transcoded 422/10bit Video and PCM
> audio from a MOV
> file (ProRes 422HQ) to a raw DV50 (422/8bit) file:
>
> ffmpeg -i SD-MOV.mov -target pal-dv50
> SD-DV50.dv
>
> [......]
>
>
> 205M SD-DV50.dv (ffmpeg re-encoded/remuxed)
> AV-info:
>
> avprobe SD-DV50.dv
> avprobe version 12.3, Copyright (c) 2007-2018 the
> Libav developers
> built on Mar 26 2018 12:39 with gcc 11 (SUSE
> Linux)
> [dv @ 0x55cdddb96440] Estimating duration from
> bitrate, this may
> be inaccurate
> Input #0, dv, from 'SD-DV50.dv':
> Metadata:
> timecode : 00:00:00:00
> Duration: 00:00:29.80, start: 0.000000, bitrate:
> 57600 kb/s
> Stream #0:0: Video: dvvideo, yuv422p,
> 720x576 [SAR
> 16:15 DAR
> 4:3], 25000 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
> Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo,
> s16, 1536 kb/s
> Stream #0:2: Audio: pcm_s16le, 48000 Hz, stereo,
> s16, 1536 kb/s
> # avprobe output
>
> ===================
>
> As seen above, it looks like ffmpeg produced wrong
> meta data for
> the DV50 video bitrate (25 Mb/s=DV25), while
> the total
> bitrate
> 57.6 Mb/s is correct. (Also similar was seen with
> ffprobe and
> Mediainfo).
>
> My VLC player or Gnome movieplayer did not
> playback
> the DV50 file,
> while ffplay did (as usual without audio?).
>
> Cin-GG miss a DV50 preset among format setting.
> However DV50 else
> loades preliminary OK in Cin-GG (via ffmpeg).
>
>
> I'll look at dv50 output preset..
>
> Fine
>
> ===============
>
> I tried also to transcode and remux 422 Video and PCM
> Audio to a
> 50 Mbps MPEG-2 I-frame only program stream.
>
> 1) MPG From MOV (ProRes 422HQ)
> ------------------------------
>
> ffmpeg -i SD-MOV.mov -c:v mpeg2video -bf 2 -b:v 50M
> -maxrate 50M
> -minrate 50M -c:a pcm_s16be -f vob SD-MP2I-50.mpg
> [....]
> Stream mapping:
> Stream #0:0 -> #0:0 (prores (native) -> mpeg2video (native))
> Stream #0:1 -> #0:1 (pcm_s24le (native) -> pcm_s16be
> (native))
> Press [q] to stop, [?] for help
> [mpeg2video @ 0x560ffd164ec0] Automatically choosing VBV
> buffer
> size of 746 kbyte
> [vob @ 0x560ffd14d180] At most 8 channels allowed for LPCM
> streams.
> Could not write header for output file #0 (incorrect codec
> parameters ?): Invalid argument
> Error initializing output stream 0:1 --
>
> ***This failed because PreRes Audio uses 16 channels:***
>
>
> yeah... interesting limitation.. and interesting number of
> channels..
>
>
> ffprobe SD-MOV.mov 2>&1 >/dev/null | grep Stream.*Audio
> Stream #0:1(eng): Audio: pcm_s24le (lpcm / 0x6D63706C),
> 48000
> Hz, 16 channels, s32 (24 bit), 18432 kb/s (default)
>
>
> 2) MPG from DV50
> ----------------
> ffmpeg -i SD-DV50.dv -c:v mpeg2video -bf 2 -b:v 50M
> -maxrate 50M
> -minrate 50M -c:a pcm_s16be -f vob SD-MP2I-50.mpg
>
> du -sh *
> 205M SD-DV50.dv
> 284M SD-MOV.mov
> 186M SD-MP2I-50.mpg
>
> avprobe SD-MP2I-50.mpg
> Input #0, mpeg, from 'SD-MP2I-50.mpg':
> Duration: 00:00:29.77, start: 0.540000, bitrate: 52167 kb/s
> Stream #0:0[0x1e0]: Video: mpeg2video (4:2:2), yuv422p(tv,
> progressive), 720x576 [SAR 16:15 DAR 4:3], 50000 kb/s, 25
> fps, 25
> tbr, 90k tbn, 50 tbc
> Stream #0:1[0xa0]: Audio: pcm_dvd, 48000 Hz, 2
> channels, s16,
> 1536 kb/s
>
> ***** The SD-MP2I-50.mpg file size is here 90% of DV50
> ********
>
> The SD-MP2I-50.mpg playback ok with VLC, Gnome movieplayer,
> ffplay, and loads and playback in Cin-GG
> The audio volume seems low (weak), but can probably be
> adjusted
> higher with ffmpeg
>
>
> well, but I missed keyframe parameter? bitrate is big but I
> think without special param ffmpeg still will not make all-I
> mpeg2 stream..?
>
>
>
> The first Video part of my ffmpeg script was based on this
> standard FFmpeg Howto for
> "MPEG-2 I-frame only Highest Quality Encoding", which didn't
> include a keyframe parameter !?
> https://brunosan.eu/images/ffmpeg_howto.html#Encoding_MPEG-2_I-frame_only_in_Highest_Quality
> <https://brunosan.eu/images/ffmpeg_howto.html#Encoding_MPEG-2_I-frame_only_in_Highest_Quality>
>
> ffmpeg -i <input_file> -vcodec mpeg2video -pix_fmt yuv422p -qscale
> 1 -qmin 1 -intra -an output.m2v
>
>
> you missed
>
> -intra?
Thanks for reviewing. "-intra" should definitely be there, and I know I
used it before editing and troubleshooting the audiopart, removing -an.
Cleaned up and added also some other parameters
-q:v 1 -qmin 1 -intra
3) MP2I50 from DV50:
---------------------
ffmpeg -i SD-DV50.dv -c:v mpeg2video -q:v 1 -qmin 1 -intra -bf 2 -b:v
50M -maxrate 50M -minrate 50M -c:a pcm_s16be -f vob SD-MP2I50.mpg
[...]
Input #0, dv, from 'SD-DV50.dv':
Metadata:
timecode : 00:00:00:00
Duration: 00:00:29.80, start: 0.000000, bitrate: 57600 kb/s
Stream #0:0: Video: dvvideo, yuv422p, 720x576 [SAR 16:15 DAR 4:3],
25000 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
Stream #0:1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream #0:2: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[... a lot of vob buffer messages scrolling ....]
[vob @ 0x564dbf6a0680] packet too large, ignoring buffer limits to mux it
[vob @ 0x564dbf6a0680] buffer underflow st=1 bufi=7204 size=7680
frame= 745 fps=460 q=1.0 Lsize= 189584kB time=00:00:29.76
bitrate=52186.6kbits/s speed=18.4x
video:181698kB audio:5588kB subtitle:0kB other streams:0kB global
headers:0kB muxing overhead: 1.227127%
avprobe SD-MP2I50.mpg
avprobe version 12.3, Copyright (c) 2007-2018 the Libav developers
built on Mar 26 2018 12:39 with gcc 7 (SUSE Linux)
Input #0, mpeg, from 'SD-MP2I50.mpg':
Duration: 00:00:29.80, start: 0.540000, bitrate: 52116 kb/s
Stream #0:0[0x1e0]: Video: mpeg2video (4:2:2), yuv422p(tv,
progressive), 720x576 [SAR 16:15 DAR 4:3], 50000 kb/s, 25 fps, 25 tbr,
90k tbn, 50 tbc
Stream #0:1[0xa0]: Audio: pcm_dvd, 48000 Hz, 2 channels, s16, 1536 kb/s
================
(Re)tested also with
4) No intra (-intra)
ffmpeg -i SD-DV50.dv -c:v mpeg2video -bf 2 -b:v 50M -maxrate 50M
-minrate 50M -c:a pcm_s16be -f vob SD-MP2-50.mpg
5) Without specified Video bitrate (-b:v)
ffmpeg -i SD-DV50.dv -c:v mpeg2video -q:v 1 -qmin 1 -intra -bf 2 -c:a
pcm_s16be -f vob SD-MP2I-.mpg
6) Video only - no Audio (-an):
ffmpeg -i SD-DV50.dv -vcodec mpeg2video -q:v 1 -qmin 1 -intra -an
SD-MP2I50-an.m2v
-----------------
du -sh *
284M SD-MOV.mov
205M SD-DV50.dv
186M SD-MP2I50.mpg (3)
186M SD-MP2-50.mpg (4)
153M SD-MP2I-.mpg (5)
146M SD-MP2I50-an.m2v (6)
As seen, no size difference between -intra (3) and without intra flag
specified (4) above:
186/205 = 90% size of the input SD-DV50.dv
I would expect this due to high bitrate and some more effectiv video
compression for MPEG-2 over DV50.
While the consumer DV25/4:2:0 pal uses 5:1 intra compression, the
pro(sumer) DV50/4:2:2 uses lower 3.3:1.
-------------
7) Another, equivalent SD MPEG-2/ 422P at ML option to setup for Cin-GG/
FFMpeg preset could be:
D10 aka Sony IMX50 Encoding - a standard definition professional video
recording format. Uses intraframe
compression, 4:2:2 color subsampling and user-selectable constant video
data rate of 30, 40 or 50 Mbit/s.
422P at ML 720 × 576 25 FPS 4:2:2 Sampling 50 Mbits/s
Sony IMX50 (I only), Broadcast Contribution (I&P only)
The Howto contains both a short and a long script version.
----------------
>
> ffmpeg changes cmd line and API quickly.. (
>
> try "-g 1" and check keyframes with some linevlike those?
>
> https://snippets.bentasker.co.uk/page-1707191206-Get-Video-Keyframe-Interval-(ffprobe)-BASH.html
> <https://snippets.bentasker.co.uk/page-1707191206-Get-Video-Keyframe-Interval-(ffprobe)-BASH.html>
>
I tried to copy and paste some line from the manual url, but
If you possibly can setup an exact FF syntax to run here, I can do it ;)
>
>
>
>
> I dropped -pix_fmt yuv422p when I saw it was detected and
> automatic from the input file.
>
>
> So I added the second PCM Audio part (similar I did for SD-DV)
> according to 1. Answer at
> https://stackoverflow.com/questions/48265448/mpeg-2-program-stream-w-pcm-audio
> <https://stackoverflow.com/questions/48265448/mpeg-2-program-stream-w-pcm-audio>
>
> FFmpeg only supports muxing 16 bit PCM in a MPEG2 PS. Use
>
> ffmpeg -i "input.mov" \
> -c:v mpeg2video -pix_fmt yuv422p -bf 2 -b:v 50M -maxrate 50M
> -minrate 50M \
> -s 1920x1080 -aspect 16:9 \
> -c:a pcm_s16be -f vob "output.mpg"
>
> The -f vob is needed to force a MPEG-2 PS, else ffmpeg will select
> MPEG-1 Systems muxer.
>
>
>
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