c# - FFmpeg.AutoGen 使用 avfilter_graph_create_filter 返回 -22

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我在win7中使用了FFmpeg.AutoGen 3.2，vs2015，从FFmpeg复制了一个示例(http://ffmpeg.org/doxygen/trunk/filtering_video_8c-example.html)，

运行时

 string video = @"e:\\1.avi";
 FilterVideo fv = new FilterVideo();
 fv.filtertest(video);

返回错误代码-22:
args:video_size=640x480:pix_fmt=AV_PIX_FMT_YUV420P:time_base=1/25:pixel_aspect=1/1
无法创建缓冲区源
-22

感谢任何代表。

打击是代码:

using FFmpeg.AutoGen;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace videoFFmpegAutoGen.tool
{
    public unsafe class FilterVideo
    {

        public int open_input_file(string filename)
        {
            try
            {
                int ret;
                AVCodec* dec;
                fixed (AVFormatContext** at = &fmt_ctx)
                {
                    ret = ffmpeg.avformat_open_input(at, filename, null, null);
                }

                if (ret < 0)
                {
                    Console.WriteLine("Cannot open input file\n");
                    return ret;
                }
                ret = ffmpeg.avformat_find_stream_info(fmt_ctx, null);
                if (ret < 0)
                {
                    Console.WriteLine("Cannot find stream information\n");
                    return ret;
                }
                ret = ffmpeg.av_find_best_stream(fmt_ctx, AVMediaType.AVMEDIA_TYPE_VIDEO, -1, -1, &dec, 0);
                if (ret < 0)
                {
                    Console.WriteLine("Cannot find a video stream in the input file\n");
                    return ret;
                }



                video_stream_index = ret;

                /* create decoding context */
                dec_ctx = ffmpeg.avcodec_alloc_context3(dec);

                ffmpeg.avcodec_parameters_to_context(dec_ctx, fmt_ctx->streams[video_stream_index]->codecpar);
                ffmpeg.av_opt_set_int(dec_ctx, "refcounted_frames", 1, 0);
                /* init the video decoder */
                if ((ret = ffmpeg.avcodec_open2(dec_ctx, dec, null)) < 0)
                {
                    Console.WriteLine("Cannot open video decoder\n");
                    return ret;
                }


                return ret;
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
            finally
            {

            }

            return -1;
        }



        private string filters_descr = "scale=78:24,transpose=cclock";
        private int video_stream_index = -1;
        private AVFormatContext* fmt_ctx;
        private AVFilterGraph* filter_graph;

        AVFilterContext* buffersrc_ctx;
        private AVCodecContext* dec_ctx;
        AVFilterContext* buffersink_ctx;
        public unsafe int init_filters(string filters_descr)
        {

            int ret = 0;
            AVFilterInOut* outputs = null;
            AVFilterInOut* inputs = null;
            try
            {
                AVFilter* buffersrc = ffmpeg.avfilter_get_by_name("buffer");
                AVFilter* buffersink = ffmpeg.avfilter_get_by_name("buffersink");
                outputs = ffmpeg.avfilter_inout_alloc();
                inputs = ffmpeg.avfilter_inout_alloc();
                AVRational time_base = fmt_ctx->streams[video_stream_index]->time_base;
                filter_graph = ffmpeg.avfilter_graph_alloc();
                //string args = string.Format("video_size=%dx%d:pix_fmt=%d:time_base=%d/%d:pixel_aspect=%d/%d", dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt, time_base.num, time_base.den, dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
                string args = string.Format("video_size={0}x{1}:pix_fmt={2}:time_base={3}/{4}:pixel_aspect={5}/{6}", dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt, time_base.num, time_base.den, dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
                // string args = string.Format("video_size={0}x{1}:time_base={2}/{3}:pixel_aspect={4}/{5}", dec_ctx->width, dec_ctx->height, time_base.num, time_base.den, dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);
               // string args = string.Format("video_size={0}x{1}", dec_ctx->width, dec_ctx->height);
                Console.WriteLine("args:" + args);
                fixed (AVFilterContext** at= &buffersrc_ctx)
                {
                    ret = ffmpeg.avfilter_graph_create_filter(at, buffersrc, "in", args, null, filter_graph);
                }

                if (ret < 0)
                {
                    Console.WriteLine("Cannot create buffer source\n"+ret);
                    return ret;
                }
                fixed (AVFilterContext** at = &buffersink_ctx)
                {
                    ret = ffmpeg.avfilter_graph_create_filter(at, buffersink, "out", null, null, filter_graph);
                }

                if (ret < 0)
                {
                    Console.WriteLine("Cannot create buffer sink\n");
                    return ret;
                }
               // ret = ffmpeg.av_opt_set_int_list(buffersink_ctx, "pix_fmts", pix_fmts,AV_PIX_FMT_NONE, AV_OPT_SEARCH_CHILDREN);

                /*
                * The buffer source output must be connected to the input pad of
                * the first filter described by filters_descr; since the first
                * filter input label is not specified, it is set to "in" by
                * default.
                */
                outputs->name = ffmpeg.av_strdup("in");
                outputs->filter_ctx = buffersrc_ctx;
                outputs->pad_idx = 0;
                outputs->next = null;
                /*
                 * The buffer sink input must be connected to the output pad of
                 * the last filter described by filters_descr; since the last
                 * filter output label is not specified, it is set to "out" by
                 * default.
                 */
                inputs->name = ffmpeg.av_strdup("out");
                inputs->filter_ctx = buffersink_ctx;
                inputs->pad_idx = 0;
                inputs->next = null;

                ret = ffmpeg.avfilter_graph_parse_ptr(filter_graph, filters_descr, &inputs, &outputs, null);
                if (ret < 0)
                {
                    return ret;
                }
                ret = ffmpeg.avfilter_graph_config(filter_graph, null);
                if (ret < 0)
                {
                    return ret;
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }
            finally
            {
                ffmpeg.avfilter_inout_free(&inputs);
                ffmpeg.avfilter_inout_free(&outputs);
            }

            return ret;

        }

        long AV_NOPTS_VALUE = 1;
        //int last_pts = AV_NOPTS_VALUE;
        long last_pts = 1;

        public void display_frame(AVFrame* frame, AVRational time_base)
        {
            int x, y;
            long delay;
            sbyte* p0;
            sbyte* p;
            AVRational cq = new AVRational();
            cq.num = 1;
            cq.den = 1000000;
            if (frame->pts != AV_NOPTS_VALUE)
            {
                if (last_pts != AV_NOPTS_VALUE)
                {
                    /* sleep roughly the right amount of time;
                     * usleep is in microseconds, just like AV_TIME_BASE. */
                    delay = ffmpeg.av_rescale_q(frame->pts - last_pts, time_base, cq);
                    if (delay > 0 && delay < 1000000)
                        Thread.Sleep((int)delay);
                }
                last_pts = frame->pts;
            }

            /* Trivial ASCII grayscale display. */
            p0 = frame->data0;
            //puts("\033c");
            for (y = 0; y < frame->height; y++)
            {
                p = p0;
                //for (x = 0; x < frame->width; x++)
                //putchar(" .-+#"[*(p++) / 52]);
                //putchar('\n');
                p0 += frame->linesize[0];
            }

            //fflush(stdout);

        }

        private int AV_BUFFERSRC_FLAG_KEEP_REF = 8 ;

        public unsafe void filtertest(string inputvideo)
        {
            AVFrame* frame = ffmpeg.av_frame_alloc();
            AVFrame* filt_frame = ffmpeg.av_frame_alloc();
            try
            {

                int ret;
                AVPacket packet;


                ffmpeg.av_register_all();
                ffmpeg.avfilter_register_all();

                ret = open_input_file(inputvideo);
                if (ret < 0)
                {
                    return;
                }
                ret = init_filters(filters_descr);
                if (ret < 0)
                {
                    return;
                }

                while (true)
                {
                    ret = ffmpeg.av_read_frame(fmt_ctx, &packet);
                    if (ret < 0)
                    {
                        Console.WriteLine("Error while sending a packet to the decoder\n");
                        break;
                    }
                    if (packet.stream_index == video_stream_index)
                    {
                        ret = ffmpeg.avcodec_send_packet(dec_ctx, &packet);
                        if (ret < 0)
                        {
                            Console.WriteLine( "Error while sending a packet to the decoder\n");
                            break;
                        }
                        while (ret >= 0)
                        {
                            ret = ffmpeg.avcodec_receive_frame(dec_ctx, frame);
                            //if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                            if (ret == 999)
                            {
                                break;
                            }
                            else if (ret < 0)
                            {
                                Console.WriteLine("Error while receiving a frame from the decoder\n");
                                return;
                            } else
                            {
                                Console.WriteLine("ret::"+ret);
                            }
                            if (ret >= 0)
                            {
                                frame->pts = frame->best_effort_timestamp;
                                /* push the decoded frame into the filtergraph */
                                if (ffmpeg.av_buffersrc_add_frame_flags(buffersrc_ctx, frame, AV_BUFFERSRC_FLAG_KEEP_REF) < 0)
                                {
                                    Console.WriteLine("Error while feeding the filtergraph\n");
                                    break;
                                }
                                /* pull filtered frames from the filtergraph */
                                while (true)
                                {
                                    ret = ffmpeg.av_buffersink_get_frame(buffersink_ctx, filt_frame);
                                    //if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                                    if (ret == 999)
                                    {
                                        break;
                                    }
                                    else if (ret < 0)
                                    {
                                        return;
                                    }else
                                    {
                                        Console.WriteLine("ret2:" + ret);
                                    }


                                    display_frame(filt_frame, buffersink_ctx->inputs[0]->time_base);
                                    ffmpeg.av_frame_unref(filt_frame);
                                }
                                ffmpeg.av_frame_unref(frame);
                            }
                        }

                    }
                    ffmpeg.av_packet_unref(&packet);
                }


            }
            catch(Exception e)
            {
                Console.WriteLine(e.ToString());

            }
            finally
            {

                fixed (AVFilterGraph** at = &filter_graph)
                {
                    ffmpeg.avfilter_graph_free(at);
                }

                ffmpeg.avcodec_close(dec_ctx);

                fixed (AVFormatContext** at = &fmt_ctx)
                {
                    ffmpeg.avformat_close_input(at);
                }
                ffmpeg.av_frame_free(&frame);
                ffmpeg.av_frame_free(&filt_frame);
            }



        }


    }
}

Answer 1

我敢打赌，问题出在这一行:

string args = string.Format("video_size={0}x{1}:pix_fmt={2}:time_base={3}/{4}:pixel_aspect={5}/{6}", dec_ctx->width, dec_ctx->height, dec_ctx->pix_fmt, time_base.num, time_base.den, dec_ctx->sample_aspect_ratio.num, dec_ctx->sample_aspect_ratio.den);

pix_fmt肯定是 int而不是作为字符串传递。

所以得到 dec_ctx->pix_fmt的整数值它应该可以工作。