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|
open Avcodec
module Resampler = Swresample.Make (Swresample.FloatArray) (Swresample.Frame)
let ( %> ) f g x = g (f x)
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 time_base = { Avutil.num = 1; den = sample_rate } in
let encoder =
Audio.create_encoder ~channel_layout:Avutil.Channel_layout.stereo ~time_base
~sample_format:out_sample_format ~sample_rate codec
in
let () =
let p = Avcodec.params encoder in
Printf.printf "Codec ID: %s\n%!"
Avcodec.Audio.(string_of_id (get_params_id p))
in
let frame_size =
if List.mem `Variable_frame_size (capabilities codec) then 512
else Audio.frame_size encoder
in
let out_sample_format = Audio.find_best_sample_format codec `Dbl in
let rsp =
Resampler.create Avutil.Channel_layout.mono sample_rate
Avutil.Channel_layout.stereo ~out_sample_format sample_rate
in
let c = 2. *. pi *. 440. /. float_of_int sample_rate in
let out_file = open_out_bin Sys.argv.(1) in
for i = 0 to 2000 do
Array.init (2 * frame_size) (fun t ->
sin (float_of_int (t + (i * frame_size)) *. c))
|> Resampler.convert ~offset:10 ~length:frame_size rsp
|> Avcodec.encode encoder (Packet.to_bytes %> output_bytes out_file)
done;
Avcodec.flush_encoder encoder (Packet.to_bytes %> output_bytes out_file);
close_out out_file;
Gc.full_major ();
Gc.full_major ()
|
