<div dir="ltr"><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div>Hi,<br><br></div>Using zeranoe FFmpeg win32 build released on 2014-05-26, entiteled "ffmpeg-20140526-git-96470ca-win32...", I have noticed a very interesting bug while selecting different presets for HEVC encoding.<br>
<br></div>First, the code:<br><br><a href="https://gist.github.com/anonymous/80f13fd55eb0e6f15ff1">https://gist.github.com/anonymous/80f13fd55eb0e6f15ff1</a><br><br></div><div>It is slightly modified version of "muxing.c" example that comes with docs: the entired muxing process is repeated two times, first with one 'preset', and then with another.<br>
</div><div><br></div><div></div>Notice line# 552 and 556, particularly this segment:<br><br>if (fmt->video_codec != AV_CODEC_ID_NONE)<br>{<br> fmt->video_codec = AV_CODEC_ID_HEVC;<br> video_st = add_stream(oc, &video_codec, fmt->video_codec);<br>
switch(i)<br> {<br> case 0:<br> //er = av_opt_set(video_st->codec->priv_data, "preset", "medium",0);//works<br> er = av_opt_set(video_st->codec->priv_data, "preset", "ultrafast",0);//does not work<br>
break;<br> case 1:<br> //er = av_opt_set(video_st->codec->priv_data, "preset", "fast",0);//works<br> er = av_opt_set(video_st->codec->priv_data, "preset", "veryslow",0);//does not work<br>
break;<br> default:<br> break;<br> }<br>}<br><br></div>For this two times encoding, if I use:<br><br>av_opt_set(video_st->codec->priv_data, "preset", "medium",0);<br>
<br></div>for first time encoding, and use <br><br>av_opt_set(video_st->codec->priv_data, "preset", "fast",0);<br><br></div>for 2nd time encoding, there is apparently no problem; but, if I use:<br>
<br>av_opt_set(video_st->codec->priv_data, "preset", "ultrafast",0);<br><br></div>for 1st time encoding, and use:<br><br>av_opt_set(video_st->codec->priv_data, "preset", "veryslow",0);<br>
<br></div>for 2nd time encoding, then open_video() function fails on 2nd attempt...<br><br>Entire console log is printed as below:<br><br>x265 [info]: HEVC encoder version 1.0+38-d0acf82a77f9<br>x265 [info]: build info [Windows][GCC 4.8.2][32 bit] 8bpp<br>
x265 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX<br>x265 [info]: WPP streams / pool / frames : 9 / 4 / 1<br>x265 [info]: Main profile, Level-2 (Main tier)<br>x265 [info]: CU size : 32<br>
x265 [info]: Max RQT depth inter / intra : 1 / 1<br>x265 [info]: ME / range / subpel / merge : dia / 25 / 0 / 2<br>x265 [info]: Keyframe min / max / scenecut : 25 / 250 / 0<br>x265 [info]: Lookahead / bframes / badapt : 10 / 4 / 0<br>
x265 [info]: b-pyramid / weightp / weightb / refs: 1 / 0 / 0 / 1<br>x265 [info]: Rate Control / AQ-Strength / CUTree : ABR-400 kbps / 0.0 / 0<br>x265 [info]: tools: cfm esd rd=3 lft<br>Output #0, mp4, to 'output.mp4':<br>
Stream #0:0: Video: hevc (libx265), yuv420p, 352x288, q=2-31, 400 kb/s, 90k<br>tbn, 25 tbc<br> Stream #0:1: Audio: aac (libvo_aacenc), 44100 Hz, 2 channels, s16, 64 kb/s<br>x265 [info]: frame I: 1 Avg QP:29.00 kb/s: 248.60<br>
x265 [info]: frame P: 3 Avg QP:22.67 kb/s: 375.00<br>x265 [info]: frame B: 11 Avg QP:26.73 kb/s: 138.29<br>x265 [info]: global : 15 Avg QP:26.07 kb/s: 192.99<br>x265 [info]: consecutive B-frames: 25.0% 0.0% 0.0% 25.0% 50.0%<br>
x265 [info]: HEVC encoder version 1.0+38-d0acf82a77f9<br>x265 [info]: build info [Windows][GCC 4.8.2][32 bit] 8bpp<br>x265 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX<br>x265 [error]: maxCUSize must be the same for all encoders in a single process<br>
[libx265 @ 05e06b40] Cannot open libx265 encoder.<br><br></div>Notice the last two lines:<br><br>x265 [error]: maxCUSize must be the same for all encoders in a single process<br>[libx265 @ 05e06b40] Cannot open libx265 encoder.<br>
<br></div>Which is kind of strange, because the preset alone is not the problem - I can swap the sequence, i.e. use:<br><br>av_opt_set(video_st->codec->priv_data, "preset", "veryslow",0);<br><br>
</div>for 1st time encoding, and use:<br><br>av_opt_set(video_st->codec->priv_data, "preset", "ultrafast",0);<br><br></div>for 2nd time encoding, then still it fails at 2nd attempt only (so the presets alone work fine).<br>
<br></div>Has this been spotted before? I tried to find similar bug reports but none found so far.<br><br></div>I've been trying to figure this since a day or two now, and this is the best lead so far.<br><br></div>I hope I did not get any parameters wrong...<br>
<div><br>Feedback is very much welcome!<br><div><div><br></div></div></div></div>