return 0;
return -1;
int rtp_get_codec_info(AVCodecContext *codec, int payload_type){    switch(payload_type) {    case RTP_PT_ULAW:        codec->codec_type = CODEC_TYPE_AUDIO;        codec->codec_id = CODEC_ID_PCM_MULAW;        codec->channels = 1;        codec->sample_rate = 8000;        break;    case RTP_PT_ALAW:        codec->codec_type = CODEC_TYPE_AUDIO;        codec->codec_id = CODEC_ID_PCM_ALAW;        codec->channels = 1;        codec->sample_rate = 8000;        break;    case RTP_PT_S16BE_STEREO:        codec->codec_type = CODEC_TYPE_AUDIO;        codec->codec_id = CODEC_ID_PCM_S16BE;        codec->channels = 2;        codec->sample_rate = 44100;        break;    case RTP_PT_S16BE_MONO:        codec->codec_type = CODEC_TYPE_AUDIO;        codec->codec_id = CODEC_ID_PCM_S16BE;        codec->channels = 1;        codec->sample_rate = 44100;        break;    case RTP_PT_MPEGAUDIO:        codec->codec_type = CODEC_TYPE_AUDIO;        codec->codec_id = CODEC_ID_MP2;        break;    case RTP_PT_JPEG:        codec->codec_type = CODEC_TYPE_VIDEO;        codec->codec_id = CODEC_ID_MJPEG;        break;    case RTP_PT_MPEGVIDEO:        codec->codec_type = CODEC_TYPE_VIDEO;        codec->codec_id = CODEC_ID_MPEG1VIDEO;        break;    case RTP_PT_MPEG2TS:        codec->codec_type = CODEC_TYPE_DATA;        codec->codec_id = CODEC_ID_MPEG2TS;        break;    default:        return -1;    }    return 0;}