static void new_audio_stream(AVFormatContext *oc)

{

    AVStream *st;

    AVCodec *codec= NULL;

    AVCodecContext *audio_enc;

    enum CodecID codec_id;



    st = av_new_stream(oc, oc->nb_streams < nb_streamid_map ? streamid_map[oc->nb_streams] : 0);

    if (!st) {

        fprintf(stderr, "Could not alloc stream\n");

        ffmpeg_exit(1);

    }



    output_codecs = grow_array(output_codecs, sizeof(*output_codecs), &nb_output_codecs, nb_output_codecs + 1);

    if(!audio_stream_copy){

        if (audio_codec_name) {

            codec_id = find_codec_or_die(audio_codec_name, AVMEDIA_TYPE_AUDIO, 1,

                                         avcodec_opts[AVMEDIA_TYPE_AUDIO]->strict_std_compliance);

            codec = avcodec_find_encoder_by_name(audio_codec_name);

            output_codecs[nb_output_codecs-1] = codec;

        } else {

            codec_id = av_guess_codec(oc->oformat, NULL, oc->filename, NULL, AVMEDIA_TYPE_AUDIO);

            codec = avcodec_find_encoder(codec_id);

        }

    }



    avcodec_get_context_defaults3(st->codec, codec);



    bitstream_filters[nb_output_files] =

        grow_array(bitstream_filters[nb_output_files],

                   sizeof(*bitstream_filters[nb_output_files]),

                   &nb_bitstream_filters[nb_output_files], oc->nb_streams);

    bitstream_filters[nb_output_files][oc->nb_streams - 1]= audio_bitstream_filters;

    audio_bitstream_filters= NULL;



    avcodec_thread_init(st->codec, thread_count);



    audio_enc = st->codec;

    audio_enc->codec_type = AVMEDIA_TYPE_AUDIO;



    if(audio_codec_tag)

        audio_enc->codec_tag= audio_codec_tag;



    if (oc->oformat->flags & AVFMT_GLOBALHEADER) {

        audio_enc->flags |= CODEC_FLAG_GLOBAL_HEADER;

        avcodec_opts[AVMEDIA_TYPE_AUDIO]->flags|= CODEC_FLAG_GLOBAL_HEADER;

    }

    if (audio_stream_copy) {

        st->stream_copy = 1;

        audio_enc->channels = audio_channels;

        audio_enc->sample_rate = audio_sample_rate;

    } else {

        audio_enc->codec_id = codec_id;

        set_context_opts(audio_enc, avcodec_opts[AVMEDIA_TYPE_AUDIO], AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM, codec);



        if (audio_qscale > QSCALE_NONE) {

            audio_enc->flags |= CODEC_FLAG_QSCALE;

            audio_enc->global_quality = st->quality = FF_QP2LAMBDA * audio_qscale;

        }

        audio_enc->channels = audio_channels;

        audio_enc->sample_fmt = audio_sample_fmt;

        audio_enc->sample_rate = audio_sample_rate;

        audio_enc->channel_layout = channel_layout;

        if (avcodec_channel_layout_num_channels(channel_layout) != audio_channels)

            audio_enc->channel_layout = 0;

        choose_sample_fmt(st, codec);

        choose_sample_rate(st, codec);

    }

    audio_enc->time_base= (AVRational){1, audio_sample_rate};

    if (audio_language) {

        av_metadata_set2(&st->metadata, "language", audio_language, 0);

        av_freep(&audio_language);

    }



    /* reset some key parameters */

    audio_disable = 0;

    av_freep(&audio_codec_name);

    audio_stream_copy = 0;

}
