[Cin] mpeg2hd422p.m2ts - groundwork for a high-end preset

[Terje J. Hanssen]

While the newer h.264 and hevc are known for best compression, mpeg2 may 
have better quality at video bitrate > 30Mbps

This example capture a raw video stream (optional tape playback) from 
the camera sensor over HDMI out and transcode audio to PCM into a 
high-end mpeg2hd422p.m2ts
-input_format yuyv422 -video_size hd1080 possibly may be commented out, 
as the encoder default uses the maximum capability it get from the 
capture card ms2130 and driver v4l2

mpeg2video is difficult to get quit perfect with ffmpeg; muxing 
overhead: 6.206455% is the minimum I have achieved as in this case.

At this high bitrate, 39Mbps here, a combination with segmented 
recording is suggested and preferred to control the file sizes 
(segments) and eventually corrupted parts better.


ffmpeg -hide_banner -f v4l2 -framerate 50 -i /dev/video0 -f alsa -ac 2 
-i hw:CARD=UHD,DEV=0 -c:v mpeg2video -refs 1 -bf 2 -b:v 35M -maxrate 35M 
-minrate 35M -bufsize 38M -muxrate 38M -dc 10 -c:a pcm_bluray 
-mpegts_m2ts_mode 1 -t 30 -f mpegts mpeg2hd422p_35M.m2ts

Input #0, video4linux2,v4l2, from '/dev/video0':
   Duration: N/A, start: 79.422429, bitrate: 1658880 kb/s
   Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080, 
1658880 kb/s, 50 fps, 50 tbr, 1000k tbn
[aist#1:0/pcm_s16le @ 0x55e2664e95c0] Guessed Channel Layout: stereo
Input #1, alsa, from 'hw:CARD=UHD,DEV=0':
   Duration: N/A, start: 1749208971.359170, bitrate: 1536 kb/s
   Stream #1:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo (native) -> mpeg2video (native))
   Stream #1:0 -> #0:1 (pcm_s16le (native) -> pcm_bluray (native))
Press [q] to stop, [?] for help
[mpeg2video @ 0x55e2664d0500] Warning vbv_delay will be set to 0xFFFF 
(=VBR) as the specified vbv buffer is too large for the given bitrate!

Output #0, mpegts, to 'mpeg2hd422p_35M.m2ts':
   Metadata:
     encoder         : Lavf61.7.100
   Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, progressive), 
1920x1080, q=2-31, 35000 kb/s, 50 fps, 90k tbn
       Metadata:
         encoder         : Lavc61.19.101 mpeg2video
       Side data:
         cpb: bitrate max/min/avg: 35000000/35000000/35000000 buffer 
size: 38000000 vbv_delay: N/A
   Stream #0:1: Audio: pcm_bluray, 48000 Hz, stereo, s16, 128 kb/s
       Metadata:
         encoder         : Lavc61.19.101 pcm_bluray
[out#0/mpegts @ 0x55e2664e9740] video:128445KiB audio:5648KiB 
subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: 
6.206455%

frame= 1500 fps= 50 q=3.5 Lsize=  142416KiB time=00:00:29.98 
bitrate=38915.0kbits/s speed=0.998x