tis 2020-08-18 klockan 15:21 +0100 skrev Mark Himsley: > Sorry to drag up this old thread: > > On Mon, 19 Aug 2019 at 17:55, Thomas Mundt <tmund...@gmail.com> > wrote: > ... > > I can give you the parameters that I use for IMX50. Not sure if these are > > the best. Got the intra matrix values from an original imx file. > > > > NTSC: -c:v mpeg2video -pix_fmt yuv422p -aspect 16:9 -top 1 -flags > > +ildct+ilme+low_delay -color_range tv -color_trc smpte170m -color_primaries > > smpte170m -colorspace smpte170m -chroma_sample_location topleft > > -signal_standard bt601 -dc 10 -intra_vlc 1 -non_linear_quant 1 -ps 1 -g 1 > > -qscale:v 1 -qmin 1 -qmax 12 -b:v 49999841 -minrate 49999841 -maxrate > > 49999841 -bufsize 1668329 -rc_init_occupancy 1668329 -rc_min_vbv_use 1 > > -rc_max_vbv_use 1 -profile:v 0 -level:v 5 -intra_matrix > > 8,16,16,17,19,22,23,31,16,16,17,19,20,23,29,29,19,17,19,22,19,25,28 > > ,35,17,19,19,20,25,28,25,33,17,19,22,25,26,25,31,31,17,19,17,20,26, > > 28,35,36,19,19,19,20,22,29,32,35,16,17,19,22,25,31,28,45 > > > > PAL: -c:v mpeg2video -pix_fmt yuv422p -aspect 16:9 -top 1 -flags > > +ildct+ilme+low_delay -color_range tv -color_trc smpte170m -color_primaries > > bt470bg -colorspace bt470bg -chroma_sample_location topleft > > -signal_standard bt601 -dc 10 -intra_vlc 1 -non_linear_quant 1 -ps 1 -g 1 > > -qscale:v 1 -qmin 1 -qmax 12 -b:v 50000000 -minrate 50000000 -maxrate > > 50000000 -bufsize 2000000 -rc_init_occupancy 2000000 -rc_min_vbv_use 1 > > -rc_max_vbv_use 1 -profile:v 0 -level:v 5 -intra_matrix > > 8,16,16,17,19,22,23,31,16,16,17,19,20,23,29,29,19,17,19,22,19,25,28 > > ,35,17,19,19,20,25,28,25,33,17,19,22,25,26,25,31,31,17,19,17,20,26, > > 28,35,36,19,19,19,20,22,29,32,35,16,17,19,22,25,31,28,45 > > > > Regards, > > Thomas > > As it stands, FFmpeg from `master` cannot create 30000/1001 FPS IMX50, > and it has to be patched to allow 49999841 to be the valid bitrate, > not 499998410 which is in the source code. > Is there any movement on this issue? > Why is 49999840 in the source code as a variant on 50000000 when it > just does not work? > Is it not better to put 49999841 into the source code?
The problem is that bitrate is an integer, whereas CBR NTSC bitrate is fractional. The muxer could be made to accept a narrow range of bitrate metadata values of course. The real problem is rate control in the MPEG-2 encoder. It is currently not possible to create 50 Mbps CBR NTSC essence with lavc, so this whole discussion became moot. The proper fix for this is to implement CBR encoding via a "bytes per packet" field. /Tomas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
