[x264-devel] possible bug with b_intra_refresh

[Kelvin Chua]

i am currently doing a video telephony application via ffmpeg and
encountered a SIGSEGV whenever i increase my resolution
from QCIF to CIF or VGA. here is a backtrace:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb0d77b70 (LWP 6549)]
0x01080b52 in x264_me_search_ref () from /usr/local/lib/libx264.so.83
(gdb) bt
#0  0x01080b52 in x264_me_search_ref () from /usr/local/lib/libx264.so.83
#1  0x01077f60 in ?? () from /usr/local/lib/libx264.so.83
#2  0x0107b049 in x264_macroblock_analyse () from
/usr/local/lib/libx264.so.83
#3  0x010a34f2 in ?? () from /usr/local/lib/libx264.so.83
#4  0x010bf94b in ?? () from /usr/local/lib/libx264.so.83
#5  0x0109d5fb in ?? () from /usr/local/lib/libx264.so.83
#6  0x010a1441 in x264_encoder_encode () from /usr/local/lib/libx264.so.83
#7  0x00539b47 in ?? () from /usr/local/lib/libavcodec.so.52
#8  0x0806de81 in H264Encoder::EncodeFrame (this=0x8614498,
    in=0xb0495008
"SSSTTTVVVWXXYYZZ[\\\\\\]]^^^__aaccdeeeefffggggfeefghijjjjkklll", 'm'
<repeats 19 times>, "llkkkkllmmmmmmmm", 'l' <repeats 20 times>,
"kkjjjjjjkklll", 'm' <repeats 13 times>,
"nnoopooooooooonnmlkkkkkkkkkjjjjjjjj", 'k' <repeats 14 times>,
"jjjjjjjkkkl"..., len=460800)

*H264Encoder::EncodeFrame is a function in my app

here is my encoding parameters:
        ctx->rc_max_rate        = (int) (((float)bitrate)*0.9/1000.0);
        ctx->rc_min_rate        = ctx->rc_max_rate;
        ctx->rc_buffer_size     = ctx->rc_max_rate;
        ctx->intra_refresh      = 1;    //params.b_intra_refresh
        ctx->sliced_threads     = 1;    //params.b_sliced_threads
        ctx->me_range           = 16;    //analyse.i_me_range
        ctx->qmin               = 10;   //rc.i_qp_min
        ctx->qcompress          = 0.6;    //rc.f_qcompress
        ctx->max_qdiff          = 12;    //rc.i_qp_step
        ctx->b_quant_factor     = 1.3; //minimum 1.26 params.rc.f_pb_factor
        ctx->i_quant_factor     = 1.4; //minimum 0.78
1/params.rc.f_ip_factor
        ctx->max_b_frames       = 0;    //params.i_bframe
        ctx->keyint_min         = 10;   //min-keyint
        ctx->coder_type         = 0;    //params.b_cabac
        ctx->gop_size           = 60;   //keyint or keyint_max
        ctx->b_annexb           = 0;    //disable start code prefix
        ctx->level              = 30;
        ctx->rtp_payload_size   = MTU-100; //params.i_slice_max_size
        ctx->weighted_p_pred    = 0;    //params.analyse.i_weighted_pred
        ctx->directpred         = 1;    //params.analyse.i_direct_mv_pred
        ctx->flags |= CODEC_FLAG_PASS1;                 //PASS1
        ctx->flags &= ~CODEC_FLAG_4MV;                  //advanced
prediction

whenever i disable b_intra_refresh, everything works perfectly. however i
wanted to enable
intra_refresh as i see a huge performance boost with it on QCIF resolution.
especially on a lossy network.

Kelvin Chua
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