C ++ - 在ffmpeg中应用过滤器 [英] C++ - applying filter in ffmpeg
问题描述
AVFilter * filter = avfilter_get_by_name（yadif）;
之后，我打开过滤器上下文：
AVFilterContext * filter_ctx;
avfilter_open（& filter_ctx，filter，NULL）;
我的第一个问题是关于这个功能。 Visual Studio警告我关于 avfilter_open 已被弃用。
之后，我做：
avfilter_init_str（filter_ctx，yadif = 1：-1）;
总是失败。我试过 1：-1 而不是 yadif = 1：-1 ，但总是失败，我应该使用什么参数？
编辑：值 1 或 2 ，例如，它有效。调试它，我发现使用这个值之一，函数使用 mode = 1 或 mode = 2 。这些值的解释在这个链接。
然后，我有一个 AVFrame *框架，这是我要去隔行的框架。当最后一句话工作时，我将有过滤器和他的上下文初始化。
感谢您的帮助。
我认为你的问题是一年多的时间，但最近我不得不使用隔行的DVB-TS流，所以我可以帮助任何人遇到这个问题。 >
这些片段来自我写的完成的播放器
初始化过滤器图：
void VideoManager :: init_filter_graph（AVFrame * frame）{
if（filter_initialised）return;
int result;
AVFilter * buffer_src = avfilter_get_by_name（缓冲区）;
AVFilter * buffer_sink = avfilter_get_by_name（buffersink）;
AVFilterInOut * inputs = avfilter_inout_alloc（）;
AVFilterInOut * outputs = avfilter_inout_alloc（）;
AVCodecContext * ctx = ffmpeg.vid_stream.context;
char args [512];
int frame_fix = 0; //修复某些流上的不良宽度
if（frame-> width< 704）frame_fix = 2;
else if（frame-> width> 704）frame_fix = -16;
snprintf（args，sizeof（args），
video_size =％dx％d：pix_fmt =％d：time_base =％d /％d：pixel_aspect =％d /％d ，
frame-> width + frame_fix，
frame-> height，
frame-> format，// ctx-> pix_fmt，
ctx-> time_base .num，
ctx-> time_base.den，
ctx-> sample_aspect_ratio.num，
ctx-> sample_aspect_ratio.den）;
const char * description =yadif = 1：-1：0;
LOGD（Filter：％s - Settings：％s，description，args）;
filter_graph = avfilter_graph_alloc（）;
result = avfilter_graph_create_filter（& filter_src_ctx，buffer_src，in，args，NULL，filter_graph）;
if（result< 0）{
LOGI（Filter graph - Unable to create buffer source）;
返回;
}
AVBufferSinkParams * params = av_buffersink_params_alloc（）;
枚举AVPixelFormat pix_fmts [] = {AV_PIX_FMT_GRAY8，AV_PIX_FMT_NONE};
params-> pixel_fmts = pix_fmts;
result = avfilter_graph_create_filter（& filter_sink_ctx，buffer_sink，out，NULL，params，filter_graph）;
av_free（params）;
if（result< 0）{
LOGI（Filter graph - Unable to create buffer sink）;
返回;
}
inputs-> name = av_strdup（out）;
inputs-> filter_ctx = filter_sink_ctx;
inputs-> pad_idx = 0;
inputs-> next = NULL;
outputs-> name = av_strdup（in）;
outputs-> filter_ctx = filter_src_ctx;
输出 - > pad_idx = 0;
outputs-> next = NULL;
result = avfilter_graph_parse_ptr（filter_graph，description，& inputs，& outputs，NULL）;
if（result< 0）LOGI（avfilter_graph_parse_ptr ERROR）;
result = avfilter_graph_config（filter_graph，NULL）;
if（result< 0）LOGI（avfilter_graph_config ERROR）;
filter_initialised = true;
}
当从流中处理视频数据包时，检查它是否是隔行扫描帧并将帧发送到过滤器。然后，过滤器会将去隔行扫描的帧返回给您。
void FFMPEG :: process_video_packet（AVPacket * pkt）{
int got;
AVFrame * frame = vid_stream.frame;
avcodec_decode_video2（vid_stream.context，frame，& got，pkt）;
if（got）{
if（！frame-> interlaced_frame）{// not interlaced
Video.add_av_frame（frame，0）;
} else {
if（！Video.filter_initialised）{
Video.init_filter_graph（frame）;
}
av_buffersrc_add_frame_flags（Video.filter_src_ctx，frame，AV_BUFFERSRC_FLAG_KEEP_REF）;
int c = 0;
while（true）{
AVFrame * filter_frame = ffmpeg.vid_stream.filter_frame;
int result = av_buffersink_get_frame（Video.filter_sink_ctx，filter_frame）;
if（result == AVERROR（EAGAIN）|| result == AVERROR（AVERROR_EOF））break;
if（result< 0）return;
Video.add_av_frame（filter_frame，c ++）;
av_frame_unref（filter_frame）;
}
}
}
}
希望这有助于任何人，因为找到关于ffmpeg的信息是艰难的。
I'm trying to deinterlace a frame using ffmpeg (latest release). Related with this question, I can get the filter I want using this sentence:
AVFilter *filter = avfilter_get_by_name("yadif");
After that, I open the filter context as:
AVFilterContext *filter_ctx;
avfilter_open(&filter_ctx, filter, NULL);
My first question is about this function. Visual Studio warns me about avfilter_open is deprecated. Which is the alternative?
After that, I do:
avfilter_init_str(filter_ctx, "yadif=1:-1");
And always fails. I've tried "1:-1" instead "yadif=1:-1", but always fails too, what parameter I should use?
EDIT: A value of "1" or "2", for example, it works. Debuging it, I found that with one of this values, the function uses mode=1 or mode=2. The explanation of those values is in this link.
Then, I have a AVFrame *frame that is the frame I want to deinterlace. When the last sentence work, I'll have the filter and his context init. How do I apply this filter to my frame?
Thanks for your help.
I undertsnad your question is over a year now but recently I had to work with interlaced DVB-TS streams so I might be able to help anybody else coming across this subject.
These snippets are from a finished player I've written
Initialise the filter graph:
void VideoManager::init_filter_graph(AVFrame *frame) {
if (filter_initialised) return;
int result;
AVFilter *buffer_src = avfilter_get_by_name("buffer");
AVFilter *buffer_sink = avfilter_get_by_name("buffersink");
AVFilterInOut *inputs = avfilter_inout_alloc();
AVFilterInOut *outputs = avfilter_inout_alloc();
AVCodecContext *ctx = ffmpeg.vid_stream.context;
char args[512];
int frame_fix = 0; // fix bad width on some streams
if (frame->width < 704) frame_fix = 2;
else if (frame->width > 704) frame_fix = -16;
snprintf(args, sizeof(args),
"video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d",
frame->width + frame_fix,
frame->height,
frame->format,// ctx->pix_fmt,
ctx->time_base.num,
ctx->time_base.den,
ctx->sample_aspect_ratio.num,
ctx->sample_aspect_ratio.den);
const char *description = "yadif=1:-1:0";
LOGD("Filter: %s - Settings: %s", description, args);
filter_graph = avfilter_graph_alloc();
result = avfilter_graph_create_filter(&filter_src_ctx, buffer_src, "in", args, NULL, filter_graph);
if (result < 0) {
LOGI("Filter graph - Unable to create buffer source");
return;
}
AVBufferSinkParams *params = av_buffersink_params_alloc();
enum AVPixelFormat pix_fmts[] = { AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE };
params->pixel_fmts = pix_fmts;
result = avfilter_graph_create_filter(&filter_sink_ctx, buffer_sink, "out", NULL, params, filter_graph);
av_free(params);
if (result < 0) {
LOGI("Filter graph - Unable to create buffer sink");
return;
}
inputs->name = av_strdup("out");
inputs->filter_ctx = filter_sink_ctx;
inputs->pad_idx = 0;
inputs->next = NULL;
outputs->name = av_strdup("in");
outputs->filter_ctx = filter_src_ctx;
outputs->pad_idx = 0;
outputs->next = NULL;
result = avfilter_graph_parse_ptr(filter_graph, description, &inputs, &outputs, NULL);
if (result < 0) LOGI("avfilter_graph_parse_ptr ERROR");
result = avfilter_graph_config(filter_graph, NULL);
if (result < 0) LOGI("avfilter_graph_config ERROR");
filter_initialised = true;
}
When processing the video packets from the stream, check if it is an interlaced frame and send the frame off to the filter. The filter will then return the de-interlaced frames back to you.
void FFMPEG::process_video_packet(AVPacket *pkt) {
int got;
AVFrame *frame = vid_stream.frame;
avcodec_decode_video2(vid_stream.context, frame, &got, pkt);
if (got) {
if (!frame->interlaced_frame) { // not interlaced
Video.add_av_frame(frame, 0);
} else {
if (!Video.filter_initialised) {
Video.init_filter_graph(frame);
}
av_buffersrc_add_frame_flags(Video.filter_src_ctx, frame, AV_BUFFERSRC_FLAG_KEEP_REF);
int c = 0;
while (true) {
AVFrame *filter_frame = ffmpeg.vid_stream.filter_frame;
int result = av_buffersink_get_frame(Video.filter_sink_ctx, filter_frame);
if (result == AVERROR(EAGAIN) || result == AVERROR(AVERROR_EOF)) break;
if (result < 0) return;
Video.add_av_frame(filter_frame, c++);
av_frame_unref(filter_frame);
}
}
}
}
Hope this helps anyone because finding information about ffmpeg is tough going.
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