On 01/06/15 19:53, Michael Niedermayer wrote: > On Mon, Jun 01, 2015 at 04:43:12PM +0200, Christoph Gerstbauer wrote: >> Hello >> >> I am testing the standard "conformness" of ffmpegs IMX50 (Mpeg2 >> I-frame, MXF) encoder. >> >> I mentioned via ffprobe or via encoding that ffmpeg does encode a >> NTSC framesize of: "208542". >> But the SMPTE Standard 356M-2001 specifies this vlaue with "208541". >> For PAL there is no problem, both framesizes are "250000". >> >> So at the encoding params I have to set the following: >> >> -bufsize 2000000 (set ratecontrol buffer size (in bits)) >> SMPTE for PAL: max coded frame size = 250,000 BYTES = 2000000 bits >> SMPTE for NTSC: max codec frame size = 208,541 BYTES = 1668328 bits >> -rc_init_occupancy 2000000 (number of bits which should be loaded >> into the rc buffer before decoding starts) >> SMPTE for PAL: max coded frame size = 250,000 BYTES = 2000000 bits >> SMPTE for NTSC: max codec frame size = 208,541 BYTES = 1668328 bits >> >> But at the NTSC encoding I get get there errors: >> >> C:\Users\gersti>ffmpegnew -i "C:\Users\gersti\D-10_NTSC.mxf" -map >> 0:v -map 0:a -c:v mpeg2video -r 30000/1001 -pix_fmt yuv422p -aspect >> 4:3 -minr >> ate 50000k -maxrate 50000k -b:v 50000k -g 1 -flags > > 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. > > check yourself: 208541 * 8 * 30000/1001 > > > [...] > > -- 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
