[Libav-user] HLS options problem

Paul B Mahol onemda at gmail.com
Tue Aug 13 14:40:11 CEST 2013

On 8/13/13, Andrey Mochenov <andrey2067 at gmail.com> wrote:
> Hi gentlemen,
> We are using FFmpeg libraries git-ee94362 libavformat v55.2.100.
> We are trying to write a simple HLS code example based on muxing.c standard
> one.
> Let be two input streams, video and audio (they can be synthetic, doesn't
> matter).
> Our purpose is to mux them into M3U8 playlist using HLS.
> Suppose, duration of every TS segment file be 3 sec, and the desirable
> maximum number of entries in M3U8 output file be 100.
> From the FFmpeg application sources, one can see that the Apple HTTP Live
> Streaming segmenter implemented in hlsenc.c file.
> And the relevant options there are, as well: "hls_list_size", "hls_time",
> etc.
> The problem is that we have not succeeded to set/get/find these options in
> a conventional way, as shown in the following code:
> // Here is a part of main() program
> int64_t i1 = 0;
> void *target_obj;
> AVFormatContext *ofmt_ctx = NULL;
> AVOutputFormat *ofmt = NULL;
> avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, "Example_Out.m3u8");
> ofmt = ofmt_ctx->oformat;
> // The relevant options ("hls_list_size", "hls_time") are located under
> ofmt->priv_class->option.
> // But AVClass *priv_class is not the first member of the AVOutputFormat.
> // So, due to the documentation, av_opt_find...(), av_opt_get...() and
> av_opt_set...()
> // cannot be used for options within AVOutputFormat.
> // In practice, any of the following three lines causes exception.
> const AVOption *o = av_opt_find2(ofmt, "segment_list_size", NULL,
> 0,  AV_OPT_SEARCH_CHILDREN, &target_obj);
> av_opt_get_int(ofmt, "segment_list_size", AV_OPT_SEARCH_CHILDREN, &i1);
> av_opt_set_int(ofmt, "segment_list_size", 10, AV_OPT_SEARCH_CHILDREN);
> Our question: If there is a way to overcome the problem, i.e. to
> set/get/find options for AVOutputFormat, like for AVCodecContext (for
> example)?

Why for AVOutputFormat? Isn't what you need AVFormatContext ?
> Thank you,
> Andrey Mochenov.

More information about the Libav-user mailing list