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|
open Avutil
module FrameToS32Bytes =
Swresample.Make (Swresample.Frame) (Swresample.S32Bytes)
let () =
if Array.length Sys.argv < 4 then (
Printf.eprintf
" usage: %s input_file format audio_output_file\n\
\ API example program to show how to read audio frames from an \
input file.\n\
\ This program reads best audio frames from a file, decodes them, \
and writes decoded\n\
\ audio frames to a rawaudio file named audio_output_file.\n"
Sys.argv.(0);
exit 1);
Log.set_level `Debug;
Log.set_callback print_string;
let audio_output_filename = Sys.argv.(3) ^ ".raw" in
let audio_output_file = open_out_bin audio_output_filename in
let format =
match Av.Format.find_input_format Sys.argv.(2) with
| Some f -> f
| None -> failwith ("Could not find format: " ^ Sys.argv.(2))
in
let input = Av.open_input ~format Sys.argv.(1) in
let idx, istream, icodec = Av.find_best_audio_stream input in
let options = [`Engine_soxr] in
let rsp =
FrameToS32Bytes.from_codec ~options icodec Avutil.Channel_layout.stereo
44100
in
let rec f () =
match Av.read_input ~audio_frame:[istream] input with
| `Audio_frame (i, frame) when i = idx ->
FrameToS32Bytes.convert rsp frame |> output_bytes audio_output_file;
f ()
| exception Avutil.Error `Eof -> ()
| _ -> f ()
in
f ();
Av.get_input istream |> Av.close;
close_out audio_output_file;
Printf.printf
"Play the output audio file with the command:\n\
ffplay -f %s -ac 2 -ar 44100 %s\n"
(Option.get (Sample_format.get_name `S32)
^ if Sys.big_endian then "be" else "le")
audio_output_filename;
Gc.full_major ();
Gc.full_major ()
|
