[FFmpeg-user] IMX50 NTSC framesize differs to the SMPTE 356M-2001 Standard - why?

[Christoph Gerstbauer]

>> yes, this happens because 50mbit/sec is not correct
>> a max framesize of 208541 results in a bit rate of max
>> 49.999840 mbit/sec, IIUC thats what the spec means by 50mbit/sec
> The spec actually says "Up to 50Mb/s" and "Up to 208541" that being the
> highest value that comes out below the the 50Mb/s. So I tend to agree
> with Michael.
>

Hi, i have made a short excel calulation and I think that these 
settings/syntaxes should be the correct ones for PAL/NTSC D-10:
Do you agree?


	
	
	
	
	
	
	minrate

	
	framerate 	max coded 	bits/byte 	bufsize 	
	maxrate

	
	
	framesize (Bytes) 	
	rc_init_occupancy 	video bitrate
IMX50 	PAL 	25 	250000 	8 	2000000 	
	50000000

	
	
		
	
	
	
IMX40 	PAL 	25 	200000 	8 	1600000 	
	40000000

	
	
		
	
	
	
IMX30 	PAL 	25 	150000 	8 	1200000 	
	30000000

	
	
		
	
	
	

	
	
		
	
	
	

	
	
		
	
	
	
IMX50 	NTSC 	29,97003 	208541 	8 	1668328 	
	49999840,16

	
	
		
	
	
	
IMX40 	NTSC 	29,97003 	166833 	8 	1334664 	
	39999920,08

	
	
		
	
	
	
IMX30 	NTSC 	29,97003 	125125 	8 	1001000 	
	30000000



Syntaxes:

PAL

IMX50 16bit 8ch

-map 0:v -map 0:a -c:v mpeg2video -s 720x608 -r 25 -pix_fmt yuv422p 
-aspect 4:3 -minrate 50000000 -maxrate 50000000 -b:v 50000000 -g 1 
-flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 2000000 -rc_init_occupancy 
2000000 -rc_max_vbv_use 1 -rc_min_vbv_use 1 -c:a pcm_s16le -ar 48000 -ac 
8 -f mxf_d10 -timecode 12:34:56:11

IMX40 16bit 8ch

-map 0:v -map 0:a -c:v mpeg2video -s 720x608 -r 25 -pix_fmt yuv422p 
-aspect 4:3 -minrate 40000000 -maxrate 40000000 -b:v 40000000 -g 1 
-flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 1600000 -rc_init_occupancy 
1600000 -rc_max_vbv_use 1 -rc_min_vbv_use 1 -c:a pcm_s16le -ar 48000 -ac 
8 -f mxf_d10 -timecode 12:34:56:11

IMX30 16bit 8ch

-map 0:v -map 0:a -c:v mpeg2video -s 720x608 -r 25 -pix_fmt yuv422p 
-aspect 4:3 -minrate 30000000 -maxrate 30000000 -b:v 30000000 -g 1 
-flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 1200000 -rc_init_occupancy 
1200000 -rc_max_vbv_use 1 -rc_min_vbv_use 1 -c:a pcm_s16le -ar 48000 -ac 
8 -f mxf_d10 -timecode 12:34:56:11

---------------------------------------------------

NTSC

IMX50 16bit 8ch

-map 0:v -map 0:a -c:v mpeg2video -s 720x512 -r 30000/1001 -pix_fmt 
yuv422p -aspect 4:3 -minrate 49999840 -maxrate 49999840 -b:v 49999840 -g 
1 -flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 1668328 -rc_init_occupancy 
1668328 -rc_max_vbv_use 1 -rc_min_vbv_use 1 -c:a pcm_s16le -ar 48000 -ac 
8 -f mxf_d10 -timecode 12:34:56:11

IMX40 16bit 8ch

-map 0:v -map 0:a -c:v mpeg2video -s 720x512 -r 30000/1001 -pix_fmt 
yuv422p -aspect 4:3 -minrate 39999920 -maxrate 39999920 -b:v 39999920 -g 
1 -flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 1334664 -rc_init_occupancy 
1334664 -rc_max_vbv_use 1 -rc_min_vbv_use 1 -c:a pcm_s16le -ar 48000 -ac 
8 -f mxf_d10 -timecode 12:34:56:11

IMX30 16bit 8ch

-map 0:v -map 0:a -c:v mpeg2video -s 720x512 -r 30000/1001 -pix_fmt 
yuv422p -aspect 4:3 -minrate 30000000 -maxrate 30000000 -b:v 30000000 -g 
1 -flags +ildct+ilme+low_delay -intra_vlc 1 -non_linear_quant 1 -ps 1 
-qmin 1 -qmax 3 -top 1 -dc 10 -bufsize 1001000 -rc_init_occupancy 
1001000 -rc_max_vbv_use 1 -rc_min_vbv_use 1 -c:a pcm_s16le -ar 48000 -ac 
8 -f mxf_d10 -timecode 12:34:56:11


Best Regards
Christoph