X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=x264_encoder.cpp;h=9874519362aadf8a3059eb77f2e797243d230459;hb=c3a08ff6100840205d295a58d6bf340aa20afde0;hp=e19a86917d3f110c76757fcf70dff9a1c1bea51d;hpb=16c0e5da7fa7b4eeea79470c24697a1ba193f071;p=nageru diff --git a/x264_encoder.cpp b/x264_encoder.cpp index e19a869..9874519 100644 --- a/x264_encoder.cpp +++ b/x264_encoder.cpp @@ -14,6 +14,24 @@ extern "C" { using namespace std; +namespace { + +void update_vbv_settings(x264_param_t *param) +{ + if (global_flags.x264_vbv_buffer_size < 0) { + param->rc.i_vbv_buffer_size = param->rc.i_bitrate; // One-second VBV. + } else { + param->rc.i_vbv_buffer_size = global_flags.x264_vbv_buffer_size; + } + if (global_flags.x264_vbv_max_bitrate < 0) { + param->rc.i_vbv_max_bitrate = param->rc.i_bitrate; // CBR. + } else { + param->rc.i_vbv_max_bitrate = global_flags.x264_vbv_max_bitrate; + } +} + +} // namespace + X264Encoder::X264Encoder(AVOutputFormat *oformat) : wants_global_headers(oformat->flags & AVFMT_GLOBALHEADER) { @@ -83,22 +101,54 @@ void X264Encoder::init_x264() param.rc.i_rc_method = X264_RC_ABR; param.rc.i_bitrate = global_flags.x264_bitrate; - if (global_flags.x264_vbv_buffer_size < 0) { - param.rc.i_vbv_buffer_size = param.rc.i_bitrate; // One-second VBV. - } else { - param.rc.i_vbv_buffer_size = global_flags.x264_vbv_buffer_size; - } - if (global_flags.x264_vbv_max_bitrate < 0) { - param.rc.i_vbv_max_bitrate = param.rc.i_bitrate; // CBR. - } else { - param.rc.i_vbv_max_bitrate = global_flags.x264_vbv_max_bitrate; + update_vbv_settings(¶m); + if (param.rc.i_vbv_max_bitrate > 0) { + // If the user wants VBV control to cap the max rate, it is + // also reasonable to assume that they are fine with the stream + // constantly being around that rate even for very low-complexity + // content; the obvious and extreme example being a static + // black picture. + // + // One would think it's fine to have low-complexity content use + // less bitrate, but it seems to cause problems in practice; + // e.g. VLC seems to often drop the stream (similar to a buffer + // underrun) in such cases, but only when streaming from Nageru, + // not when reading a dump of the same stream from disk. + // I'm not 100% sure whether it's in VLC (possibly some buffering + // in the HTTP layer), in microhttpd or somewhere in Nageru itself, + // but it's a typical case of problems that can arise. Similarly, + // TCP's congestion control is not always fond of the rate staying + // low for a while and then rising quickly -- a variation on the same + // problem. + // + // We solve this by simply asking x264 to fill in dummy bits + // in these cases, so that the bitrate stays reasonable constant. + // It's a waste of bandwidth, but it makes things go much more + // smoothly in these cases. (We don't do it if VBV control is off + // in general, not the least because it makes no sense and x264 + // thus ignores the parameter.) + param.rc.b_filler = 1; } // Occasionally players have problem with extremely low quantizers; // be on the safe side. Shouldn't affect quality in any meaningful way. param.rc.i_qp_min = 5; - // TODO: more flags here, via x264_param_parse(). + for (const string &str : global_flags.x264_extra_param) { + const size_t pos = str.find(','); + if (pos == string::npos) { + if (x264_param_parse(¶m, str.c_str(), nullptr) != 0) { + fprintf(stderr, "ERROR: x264 rejected parameter '%s'\n", str.c_str()); + } + } else { + const string key = str.substr(0, pos); + const string value = str.substr(pos + 1); + if (x264_param_parse(¶m, key.c_str(), value.c_str()) != 0) { + fprintf(stderr, "ERROR: x264 rejected parameter '%s' set to '%s'\n", + key.c_str(), value.c_str()); + } + } + } x264_param_apply_profile(¶m, "high"); @@ -133,7 +183,10 @@ void X264Encoder::init_x264() void X264Encoder::encoder_thread_func() { - nice(5); // Note that x264 further nices some of its threads. + if (nice(5) == -1) { // Note that x264 further nices some of its threads. + perror("nice()"); + // No exit; it's not fatal. + } init_x264(); bool frames_left; @@ -176,6 +229,7 @@ void X264Encoder::encode_frame(X264Encoder::QueuedFrame qf) x264_nal_t *nal = nullptr; int num_nal = 0; x264_picture_t pic; + x264_picture_t *input_pic = nullptr; if (qf.data) { x264_picture_init(&pic); @@ -189,23 +243,34 @@ void X264Encoder::encode_frame(X264Encoder::QueuedFrame qf) pic.img.i_stride[1] = WIDTH / 2 * sizeof(uint16_t); pic.opaque = reinterpret_cast(intptr_t(qf.duration)); + input_pic = &pic; + } + + // See if we have a new bitrate to change to. + unsigned new_rate = new_bitrate_kbit.exchange(0); // Read and clear. + if (new_rate != 0) { if (speed_control) { - speed_control->before_frame(float(free_frames.size()) / X264_QUEUE_LENGTH, X264_QUEUE_LENGTH, 1e6 * qf.duration / TIMEBASE); - } - x264_encoder_encode(x264, &nal, &num_nal, &pic, &pic); - if (speed_control) { - speed_control->after_frame(); - } - } else { - if (speed_control) { - speed_control->before_frame(float(free_frames.size()) / X264_QUEUE_LENGTH, X264_QUEUE_LENGTH, 1e6 * qf.duration / TIMEBASE); - } - x264_encoder_encode(x264, &nal, &num_nal, nullptr, &pic); - if (speed_control) { - speed_control->after_frame(); + speed_control->set_config_override_function([new_rate](x264_param_t *param) { + param->rc.i_bitrate = new_rate; + update_vbv_settings(param); + }); + } else { + x264_param_t param; + x264_encoder_parameters(x264, ¶m); + param.rc.i_bitrate = new_rate; + update_vbv_settings(¶m); + x264_encoder_reconfig(x264, ¶m); } } + if (speed_control) { + speed_control->before_frame(float(free_frames.size()) / X264_QUEUE_LENGTH, X264_QUEUE_LENGTH, 1e6 * qf.duration / TIMEBASE); + } + x264_encoder_encode(x264, &nal, &num_nal, input_pic, &pic); + if (speed_control) { + speed_control->after_frame(); + } + // We really need one AVPacket for the entire frame, it seems, // so combine it all. size_t num_bytes = buffered_sei.size();