The change is gradual, not instant. It will change over time. At least it did
in my testing of directly modifying the x264 code. Set it to crf 45 and then
change to 12. It will do something for sure.
-------- Original message --------From: 田浩杨 <[email protected]> Date: 16/12/2019
10:46 (GMT+01:00) To: "This list is about using libavcodec, libavformat,
libavutil,libavdevice and libavfilter." <[email protected]> Subject:
[Libav-user] 回复： videorate realtime-adjusting Excuse me, I have called the
API-'reconfig_encoder' to controll the bitrate of X264-encoder in real time,
but I found it didn't work by network monitor. I changed the
AVCodecContext->bit_rate \ AVCodecContext->rc_max_rate \
AVCodecContext->rc_buffer_size. And I checked the return value of
'x264_encoder_reconfig' which equals to zero. So whats the problem?
------------------ 原始邮件 ------------------发件人: "Strahinja
Radman"<[email protected]>;发送时间: 2019年12月2日(星期一) 下午5:03收件人: "This list is
about using libavcodec, libavformat, libavutil,libavdevice and
libavfilter."<[email protected]>;主题: Re: [Libav-user] videorate
realtime-adjustingOn Mon, Dec 2, 2019 at 9:29 AM 田浩杨 <[email protected]> wrote:I
have a question. How can I modify the video-encode bitrate in real time during
coding after the video encoder has been turned on? Here's what I did (take
x264-encoder as an example) :step1.Modified the definition of structural
AVCoder to add a function pointer. int
(*valid_context)(AVCodecContext*);step2.Added function definition to enable the
codec rate of x264.static int X264_config(AVCodecContext* avctx){
X264Context* x4 = avctx->priv_data; if(avctx->bit_rate){
x4->params.rc.i_bitrate = avctx->bit_rate / 1000; } avctx->bit_rate =
x4->params.rc.i_bitrate*1000; return 0;}step3.build AVCodec.AVCodec
ff_libx264_encoder = { .name = "libx264", .long_name =
NULL_IF_CONFIG_SMALL("libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10"),
.type = AVMEDIA_TYPE_VIDEO, .id =
AV_CODEC_ID_H264, .priv_data_size = sizeof(X264Context), .init
= X264_init, // .valid_context = X264_config, // .encode2
= X264_frame, .close = X264_close, .capabilities =
AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AUTO_THREADS, .priv_class =
&x264_class, .defaults = x264_defaults, .init_static_data =
X264_init_static, .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP, .wrapper_name =
"libx264",};step4.FFmpeg interface layer.int attribute_align_arg
avcodec_valid_codec_Context(AVCodecContext* avctx){ int ret = 0; ret =
avctx->codec->valid_context(avctx); if(ret){ av_log(avctx,
AV_LOG_ERROR, "valid context error, ERROR CODE:%d\n", ret); }
return ret;}step5.Whenever the application layer needs to modify the bit rate,
then App should modify the AVCodecContext-> bit_rate, and then call the above
interface to make the Context take effect in the encoder.Because of the limited
understanding of ffmpeg. So if there is a better way, also hope to give
instruction._______________________________________________
Libav-user mailing list
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https://ffmpeg.org/mailman/listinfo/libav-user
To unsubscribe, visit link above, or email
[email protected] with subject "unsubscribe".Well, according to the
libx264.c wrapper and x264's encoder.c code, one can simply change the valueof
bitrate, bufsize, maxrate or crf in AVCodecContext, and reconfig_encoder will
invoke x264's internalAPI that will reconfigure the encoder with one or more of
the previously mentioned values. That shouldbe it. The change will be triggered
on the next sent frame. Checkout the source of libx264.c line 186.--
RegardsStrahinja Radman
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