[x264-devel] A problem in file encoding (possible bug)

[Alexander Bokovikov]

Hi, All,

Here is the FLV file sample:
http://home.bokovikov.com/ffmpeg/test.flv

Here is the command line (for FFMPEG)

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./ffmpeg -i test.flv -f ipod -vcodec libx264 -vprofile baseline -level  
30 -maxrate 10000000 -bufsize 10000000 -acodec copy -threads 0 -y  
test.m4v
================><8================

Here is the libx264 output (in FFMPEG)

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     Stream #0:0: Video: h264 (avc1 / 0x31637661), yuv420p, 720x432  
[SAR 1:1 DAR 5:3], q=-1--1, 1 tbn, 0.08 tbc
     Stream #0:1: Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo,  
131 kb/s
Stream mapping:
   Stream #0:0 -> #0:0 (h264 -> libx264)
   Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[libx264 @ 0x81ce20] VBV buffer size cannot be smaller than one frame,  
using 119999 kbit
frame=    6 fps=  2 q=0.0 size=       0kB time=00:00:00.00 bitrate=    
0.0kbits/s dup=0 drop=1238   frame=    7 fps=  2 q=0.0 size=       0kB  
time=00:00:00.00 bitrate=   0.0kbits/s dup=0 drop=1487   frame=    7  
fps=  2 q=-1.0 Lsize=    1109kB time=00:01:01.47 bitrate= 147.8kbits/s  
dup=0 drop=1531
video:122kB audio:959kB global headers:0kB muxing overhead 2.553527%
[libx264 @ 0x81ce20] frame I:4     Avg QP: 9.44  size: 23737
[libx264 @ 0x81ce20] frame P:3     Avg QP: 8.35  size:  9727
[libx264 @ 0x81ce20] mb I  I16..4: 51.6%  0.0% 48.4%
[libx264 @ 0x81ce20] mb P  I16..4: 46.7%  0.0% 17.6%  P16..4: 12.4%   
1.6%  0.7%  0.0%  0.0%    skip:21.0%
[libx264 @ 0x81ce20] coded y,uvDC,uvAC intra: 47.0% 62.6% 48.6% inter:  
7.9% 32.6% 11.0%
[libx264 @ 0x81ce20] i16 v,h,dc,p: 70% 16%  9%  5%
[libx264 @ 0x81ce20] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 30% 13%  5%   
5%  5%  6%  4%  8%
[libx264 @ 0x81ce20] i8c dc,h,v,p: 54% 23% 17%  7%
[libx264 @ 0x81ce20] kb/s:11.82
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Looks like an error occurs in the very first frame, whose size is  
obtained incorrectly. FLV looks OK in all viewers I have on my Mac.  
Both QuickTime and VLC play it correctly. Moreover, I've tried to cut- 
off the initial portion up to the second keyframe and result is  
encoded correctly. This proves that the problem is covered in the very  
first frame decoding.

I used last stable snapshot to build libx264.

Can anybody help here?

Thanks.