最简单的基于FFMPEG的转码程序 open_output_file函数报错“Cannot open video encoder for stream ...”

雷神的https://blog.csdn.net/leixiaohua1020/article/details/26838535

文章后附的代码，报错:Cannot open video encoder for stream blabla...

需要修改一下，解决方法来自，烛龙一现，https://blog.csdn.net/w_z_z_1991/article/details/53002416

“

在transcoding.c中的open_output_file函数中，修改的部分如下(只增加了13-17行)：

if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
                enc_ctx->height = dec_ctx->height;
                enc_ctx->width = dec_ctx->width;
                enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
                /* take first format from list of supported formats */
                if (encoder->pix_fmts)
                    enc_ctx->pix_fmt = encoder->pix_fmts[0];
                else
                    enc_ctx->pix_fmt = dec_ctx->pix_fmt;
                /* video time_base can be set to whatever is handy and supported by encoder */
                enc_ctx->time_base = dec_ctx->time_base;

                enc_ctx->me_range = 16; 
                enc_ctx->max_qdiff = 4;
                enc_ctx->qmin = 10; 
                enc_ctx->qmax = 51; 
                enc_ctx->qcompress = 0.6;

            } else {
                enc_ctx->sample_rate = dec_ctx->sample_rate;
                enc_ctx->channel_layout = dec_ctx->channel_layout;
                enc_ctx->channels = av_get_channel_layout_nb_channels(enc_ctx->channel_layout);
                /* take first format from list of supported formats */
                enc_ctx->sample_fmt = encoder->sample_fmts[0];
                enc_ctx->time_base = (AVRational){1, enc_ctx->sample_rate};
            }   

--------------------- 作者：烛龙一现 来源：CSDN 原文：https://blog.csdn.net/w_z_z_1991/article/details/53002416?utm_source=copy 版权声明：本文为博主原创文章，转载请附上博文链接！

”

其中enc_ctx->qmax = 51; 可以改小提高转码后视频质量。

非常感谢！！！愿雷神彼生平安幸福唉