[FFmpeg-devel] [PATCH] libavformat/assenc: Add ignore_gaps option

[wm4]

On Thu, 30 Oct 2014 04:36:28 -0500
Rodger Combs <rodger.combs at gmail.com> wrote:

> This patch lets the user ignore ReadOrder when writing ASS subtitles, which is useful when e.g. streaming output.
> 
> From d3d4cb4da2382a1d762fa1e9bfafbaf3d18cf5c5 Mon Sep 17 00:00:00 2001
> From: Rodger Combs <rodger.combs at gmail.com>
> Date: Thu, 30 Oct 2014 04:33:17 -0500
> Subject: [PATCH] libavformat/assenc: Add ignore_gaps option
> 
> ---
>  libavformat/assenc.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/assenc.c b/libavformat/assenc.c
> index 8225967..c7a1d1e 100644
> --- a/libavformat/assenc.c
> +++ b/libavformat/assenc.c
> @@ -23,6 +23,8 @@
>  #include "avformat.h"
>  #include "internal.h"
>  
> +#include "libavutil/opt.h"
> +
>  typedef struct DialogueLine {
>      int readorder;
>      char *line;
> @@ -30,12 +32,14 @@ typedef struct DialogueLine {
>  } DialogueLine;
>  
>  typedef struct ASSContext{
> +    const AVClass *class;
>      int write_ts; // 0: ssa (timing in payload), 1: ass (matroska like)
>      int expected_readorder;
>      DialogueLine *dialogue_cache;
>      DialogueLine *last_added_dialogue;
>      int cache_size;
>      int ssa_mode;
> +    int ignore_gaps;
>  }ASSContext;
>  
>  static int write_header(AVFormatContext *s)
> @@ -178,7 +182,7 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
>              return AVERROR(ENOMEM);
>          }
>          insert_dialogue(ass, dialogue);
> -        purge_dialogues(s, 0);
> +        purge_dialogues(s, ass->ignore_gaps);
>      } else {
>          avio_write(s->pb, pkt->data, pkt->size);
>      }
> @@ -192,6 +196,20 @@ static int write_trailer(AVFormatContext *s)
>      return 0;
>  }
>  
> +#define OFFSET(x) offsetof(ASSContext, x)
> +#define E AV_OPT_FLAG_ENCODING_PARAM
> +static const AVOption options[] = {
> +    { "ignore_gaps", "write events immediately, even if they're out-of-order", OFFSET(ignore_gaps), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, E },
> +    { NULL },
> +};
> +
> +static const AVClass ass_class = {
> +    .class_name = "ass muxer",
> +    .item_name  = av_default_item_name,
> +    .option     = options,
> +    .version    = LIBAVUTIL_VERSION_INT,
> +};
> +
>  AVOutputFormat ff_ass_muxer = {
>      .name           = "ass",
>      .long_name      = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
> @@ -203,4 +221,5 @@ AVOutputFormat ff_ass_muxer = {
>      .write_packet   = write_packet,
>      .write_trailer  = write_trailer,
>      .flags          = AVFMT_GLOBALHEADER | AVFMT_NOTIMESTAMPS | AVFMT_TS_NONSTRICT,
> +    .priv_class     = &ass_class,
>  };

The option name is a bit unspecific - how about "ignore_readorder"?