On 08/06/15 16:24, Michael Niedermayer wrote: > On Wed, Jun 03, 2015 at 04:28:48PM +0200, Christoph Gerstbauer wrote: >>>> 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 > > i seem to have missed this reply, my question is basicylly the same > as tims, where does the limit resulting in 39999920 come from ? > is there some specification that limits the VBV buffer size to a > lower value for "40mbit/sec" than "50mbit/sec" ? >
The VBV size for 40M will be lower than for 50M as its limited to 1 frame which is smaller (by about 25/30), its more a question of why the NTSC bitrate figure is diferent to PAL when there is no other constraint as to the maximum frame size which we are nowhere near at this bit rate. The standard "Operating Points" only provide the nominal values. > [...] -- Tim. Key Fingerprint 38CF DB09 3ED0 F607 8B67 6CED 0C0B FC44 8B0B FC83 _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
