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I'm trying to configure x264 for 1080i capturing. Most of these settings below are found in different examples. However, compiled together they don't work. ffmpeg API reports no error, but avcodec_encode_video() always returns zero.

Some of the numbers are strange to me... for example, gop_size. Isn't 250 too high?

Event you can't offer the final answer, I'm still interested in any kind of comment on this subject. 

pCodecContext->codec_type              = AVMEDIA_TYPE_VIDEO;
pCodecContext->codec_id                = CODEC_ID_H264;

pCodecContext->coder_type              = FF_CODER_TYPE_AC;
pCodecContext->flags                  |= CODEC_FLAG_LOOP_FILTER | CODEC_FLAG_INTERLACED_ME | CODEC_FLAG_INTERLACED_DCT;
pCodecContext->me_cmp                 |= 1;
pCodecContext->partitions             |= X264_PART_I8X8 | X264_PART_I4X4 | X264_PART_P8X8 | X264_PART_B8X8;
pCodecContext->me_method               = ME_UMH;
pCodecContext->me_subpel_quality       = 8;
pCodecContext->me_range                = 16;

pCodecContext->bit_rate                = 10 * 1024 * 1024; // 10 Mbps??
pCodecContext->width                   = 1920;
pCodecContext->height                  = 1080;

pCodecContext->time_base.num           = 1;    // 25 fps
pCodecContext->time_base.den           = 25;   // 25 fps

pCodecContext->gop_size                = 250; // 250
pCodecContext->keyint_min              = 25;
pCodecContext->scenechange_threshold   = 40;
pCodecContext->i_quant_factor          = 0.71f;
pCodecContext->b_frame_strategy        = 1;
pCodecContext->qcompress               = 0.6f;
pCodecContext->qmin                    = 10;
pCodecContext->qmax                    = 51;
pCodecContext->max_qdiff               = 4;
pCodecContext->max_b_frames            = 3;
pCodecContext->refs                    = 4;
pCodecContext->directpred              = 3;
pCodecContext->trellis                 = 1;
pCodecContext->flags2                 |= CODEC_FLAG2_WPRED | CODEC_FLAG2_MIXED_REFS | CODEC_FLAG2_8X8DCT | CODEC_FLAG2_FASTPSKIP;  // wpred+mixed_refs+dct8x8+fastpskip
pCodecContext->weighted_p_pred         = 2; // not implemented with interlaced ??
pCodecContext->crf                     = 22;

pCodecContext->pix_fmt                 = PIX_FMT_YUV420P;

pCodecContext->thread_count            = 0;

2 Answers2

0

You could analyze some existing 1080i h264 video files to see their parameters. I found useful for me that links:

alexander
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You should strive to avoid setting any x264 options yourself; the library itself knows best and you'll only get poor tunings from reading old source code. Use the AVOption API to set the "preset"/"tune"/"profile" options on the encoder to what you need (see x264 --help).

alex strange
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