[FFmpeg-trac] #3091(undetermined:new): High Bitrate I-frame CBR MPEG encoding causes error
FFmpeg
trac at avcodec.org
Wed Oct 30 01:02:33 CET 2013
#3091: High Bitrate I-frame CBR MPEG encoding causes error
-------------------------------------+-------------------------------------
Reporter: ortoni | Owner:
Type: defect | Status: new
Priority: normal | Component:
Version: unspecified | undetermined
Keywords: | Resolution:
Blocking: | Blocked By:
Analyzed by developer: 0 | Reproduced by developer: 0
-------------------------------------+-------------------------------------
Comment (by cehoyos):
The documentations states that the default for {{{-bt}}} is 4M (and that a
too small value is bad for quality). For some (sufficiently large)
bitrate, the default must be too small to even encode. FFmpeg is warning
that you have to increase the value. I wonder what could be changed.
{{{
$ ffmpeg -f lavfi -i testsrc=s=1920x1080 -vcodec mpeg2video -pix_fmt
yuv422p -intra -flags +ildct+ilme -b:v 150M -minrate 150M -maxrate 150M
-bufsize 47185920 -r 25 -f null -
ffmpeg version N-57552-g0e85bfe Copyright (c) 2000-2013 the FFmpeg
developers
built on Oct 30 2013 00:35:19 with gcc 4.7 (SUSE Linux)
configuration: --enable-gpl
libavutil 52. 48.100 / 52. 48.100
libavcodec 55. 39.100 / 55. 39.100
libavformat 55. 19.104 / 55. 19.104
libavdevice 55. 5.100 / 55. 5.100
libavfilter 3. 90.100 / 3. 90.100
libswscale 2. 5.101 / 2. 5.101
libswresample 0. 17.104 / 0. 17.104
libpostproc 52. 3.100 / 52. 3.100
Input #0, lavfi, from 'testsrc=s=1920x1080':
Duration: N/A, start: 0.000000, bitrate: N/A
Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 1920x1080
[SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
[mpeg2video @ 0x1bbabe0] bitrate tolerance too small for bitrate
Output #0, null, to 'pipe:':
Stream #0:0: Video: mpeg2video, yuv422p, 1920x1080 [SAR 1:1 DAR 16:9],
q=2-31, 150000 kb/s, 90k tbn, 25 tbc
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo -> mpeg2video)
Error while opening encoder for output stream #0:0 - maybe incorrect
parameters such as bit_rate, rate, width or height
}}}
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/3091#comment:3>
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