41     AVCodecParameters *par;  in derf_read_header()  local
50     par              = st->codecpar;  in derf_read_header()
51     par->codec_type  = AVMEDIA_TYPE_AUDIO;  in derf_read_header()
52     par->codec_id    = AV_CODEC_ID_DERF_DPCM;  in derf_read_header()
53     par->format      = AV_SAMPLE_FMT_S16;  in derf_read_header()
54     par->channels    = avio_rl32(pb);  in derf_read_header()
55     if (par->channels != 1 && par->channels != 2)  in derf_read_header()
57     if (par->channels == 1)  in derf_read_header()
58         par->channel_layout = AV_CH_LAYOUT_MONO;  in derf_read_header()
59     else if (par->channels == 2)  in derf_read_header()
60         par->channel_layout = AV_CH_LAYOUT_STEREO;  in derf_read_header()
62     st->duration = data_size / par->channels;  in derf_read_header()
63     par->sample_rate = 22050;  in derf_read_header()
64     par->block_align = 1;  in derf_read_header()
66     avpriv_set_pts_info(st, 64, 1, par->sample_rate);  in derf_read_header()