1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
open Avcodec
module Resampler = Swresample.Make (Swresample.FloatArray) (Swresample.Frame)
let () = Printexc.record_backtrace true
let () =
if Array.length Sys.argv < 3 then (
Printf.eprintf "Usage: %s <output file> <codec name>\n" Sys.argv.(0);
exit 1);
Avutil.Log.set_level `Debug;
Avutil.Log.set_callback print_string;
let pi = 4.0 *. atan 1.0 in
let sample_rate = 44100 in
let codec = Audio.find_encoder_by_name Sys.argv.(2) in
let out_sample_format = Audio.find_best_sample_format codec `Dbl in
let out_sample_rate = if Sys.argv.(2) = "flac" then 22050 else 44100 in
let rsp =
Resampler.create `Mono sample_rate `Stereo ~out_sample_format
out_sample_rate
in
let c = 2. *. pi *. 440. /. float_of_int sample_rate in
let filename = Sys.argv.(1) in
let format =
match Av.Format.guess_output_format ~filename () with
| None -> failwith "No format for filename!"
| Some f -> f
in
let fd = Unix.(openfile filename [O_WRONLY; O_CREAT; O_TRUNC] 0o644) in
let write = Unix.write fd in
let seek = Unix.lseek fd in
let output_opt = Hashtbl.create 2 in
Hashtbl.add output_opt "packetsize" (`Int 4096);
Hashtbl.add output_opt "foo" (`String "bla");
let output = Av.open_output_stream ~opts:output_opt ~seek write format in
let pts = ref 0L in
let time_base = { Avutil.num = 1; den = out_sample_rate } in
let opts = Hashtbl.create 2 in
Hashtbl.add opts "lpc_type" (`String "none");
Hashtbl.add opts "foo" (`String "bla");
let stream =
Av.new_audio_stream ~channels:2 ~time_base ~sample_format:out_sample_format
~sample_rate:out_sample_rate ~codec ~opts output
in
let out_frame_size =
if List.mem `Variable_frame_size (capabilities codec) then 512
else Av.get_frame_size stream
in
let audio_filter =
let in_params =
{
Avfilter.Utils.sample_rate = out_sample_rate;
channel_layout = `Stereo;
sample_format = out_sample_format;
}
in
Avfilter.Utils.init_audio_converter ~in_params ~in_time_base:time_base
~out_frame_size ()
in
assert (Hashtbl.mem opts "foo");
if Sys.argv.(2) = "flac" then assert (not (Hashtbl.mem opts "lpc_type"))
else assert (Hashtbl.mem opts "lpc_type");
assert (Hashtbl.mem output_opt "foo");
assert (not (Hashtbl.mem output_opt "packetsize"));
let on_frame frame =
Avutil.Frame.set_pts frame (Some !pts);
pts := Int64.add !pts (Int64.of_int (Avutil.Audio.frame_nb_samples frame));
Av.write_frame stream frame
in
for i = 0 to 2000 do
Array.init out_frame_size (fun t ->
sin (float_of_int (t + (i * out_frame_size)) *. c))
|> Resampler.convert rsp
|> Avfilter.Utils.convert_audio audio_filter on_frame
done;
Av.close output;
Unix.close fd;
Gc.full_major ();
Gc.full_major ()
|
