[Libav-user] building a webradio with libav

classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view
|

[Libav-user] building a webradio with libav

Nicolas Mora
Hello,

I'm trying to buid a webradio based on libav. The program would read a
list of files in sequence, transcode them, then broadcast the result on
a http stream.

I use Ubuntu 17.04 ffmpeg-libav* libraries

Ubuntu version:
libavcodec-dev:amd64 - 7:3.2.4-1build2 - amd64

the file version.h says:
#define LIBAVCODEC_VERSION_MAJOR  57
#define LIBAVCODEC_VERSION_MINOR  64
#define LIBAVCODEC_VERSION_MICRO 101

I'm based on the example program transcode.c and I'm currently stuck at
getting an output buffer correctly.

As I can see, the transcode.c file uses avio_open in the function
open_output_file to write the output data in the specified output file.

In my case I would like to skip the output file part and work directly
with a buffer in memory but I can't seem to have it right.

Instead of open_output_file, I try using avio_alloc_context to define a
in-memory context like this:

if ((output_io_context = avio_alloc_context(*av_buffer, BUFFER_SIZE, 0,
audio_buffer, &read_packet, &write_packet, NULL)) == NULL) {
   fprintf(stderr, "Could not open context\n");
   return AVERROR(ENOMEM);
}

But for some reason, the functions read_packet or write_packet are never
called when av_write_frame is called in the function encode_audio_frame.
Which means I'm wrong in my approach or in my implementation or both.

Can anyone help point where I'm wrong and guide me through the right way
to handle the output data with the AVFormatContext structure?

Thanks in advance
_______________________________________________
Libav-user mailing list
[hidden email]
http://ffmpeg.org/mailman/listinfo/libav-user