ffmpeg transcoding.c проблемы с «измерения не установлены»

парни

Я пытаюсь решить эту проблему в примере transcoding.c о FFMPEG. но я не знаю, как подойти …

это моя проблема

[libx264 @ 00000000022c7120] размеры не установлены

Невозможно открыть видеокодер для потока № 0

Произошла ошибка: неверный аргумент

вот мой код, чтобы немного исправить пример transcoding.c

static int open_output_file(const char *filename)
{
AVStream *out_stream;
AVStream *in_stream;
AVCodecContext *dec_ctx, *enc_ctx;
AVCodec *encoder;
int ret;
unsigned int i;

ofmt_ctx = NULL;

avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, filename);

if (!ofmt_ctx) {
av_log(NULL, AV_LOG_ERROR, "Could not create output context\n");
return AVERROR_UNKNOWN;
}for (i = 0; i < ifmt_ctx->nb_streams; i++) {

in_stream = ifmt_ctx->streams[i];

out_stream = avformat_new_stream(ofmt_ctx, NULL);

if (!out_stream) {
av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n");
return AVERROR_UNKNOWN;
}dec_ctx = avcodec_alloc_context3(in_stream->codec->codec);
enc_ctx = avcodec_alloc_context3(out_stream->codec->codec);printf("codec name : %s \n", avcodec_get_name(enc_ctx->codec_id));if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO || dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {/* in this example, we choose transcoding to same codec */
encoder = avcodec_find_encoder(dec_ctx->codec_id);//encoder = avcodec_find_encoder(AV_CODEC_ID_H264);

if (!encoder) {
av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
return AVERROR_INVALIDDATA;
}/* In this example, we transcode to same properties (picture size,
* sample rate etc.). These properties can be changed for output
* streams easily using filters */
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 */
//enc_ctx->pix_fmt = encoder->pix_fmts[0];
enc_ctx->pix_fmt = AV_PIX_FMT_YUV420P;

/* video time_base can be set to whatever is handy and supported by encoder */
enc_ctx->time_base = dec_ctx->time_base;

}

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.num = 1;
enc_ctx->time_base.den = enc_ctx->sample_rate;
}/* Third parameter can be used to pass settings to encoder */
ret = avcodec_open2(enc_ctx, encoder, NULL);if (ret < 0) {
cout << "ret<0" << endl;
av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
return ret;
}}
else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) {
av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i);
return AVERROR_INVALIDDATA;
}
else {
/* if this stream must be remuxed */
ret = avcodec_copy_context(ofmt_ctx->streams[i]->codec, ifmt_ctx->streams[i]->codec);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Copying stream context failed\n");
return ret;
}
}

if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

av_dump_format(ofmt_ctx, 0, filename, 1);

if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) {
ret = avio_open(&ofmt_ctx->pb, filename, AVIO_FLAG_WRITE);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Could not open output file '%s'", filename);
return ret;
}
}

/* init muxer, write output file header */
ret = avformat_write_header(ofmt_ctx, NULL);
if (ret < 0) {
av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n");
return ret;
}

return 0;

}

какую часть я не проверял ….

и почему avcodec_open2 не работает …