[FFmpeg-devel,v2] avformat/hlsenc: add hls_fmp4_init_resend option

add option for resend init file after m3u8 refresh everytime.

Signed-off-by: Steven Liu <lq@chinaffmpeg.org>
---
 doc/muxers.texi      |  3 +++
 libavformat/hlsenc.c | 41 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 39 insertions(+), 5 deletions(-)

Ignore this patch please, I will submit v3 to modify all the refresh to resend.

> 2020年4月7日 下午1:46，Steven Liu <lq@chinaffmpeg.org> 写道：
> 
> add option for resend init file after m3u8 refresh everytime.
> 
> Signed-off-by: Steven Liu <lq@chinaffmpeg.org>
> ---
> doc/muxers.texi      |  3 +++
> libavformat/hlsenc.c | 41 ++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 39 insertions(+), 5 deletions(-)
> 
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index d304181671..8f2dcc4610 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -836,6 +836,9 @@ fmp4 files may be used in HLS version 7 and above.
> @item hls_fmp4_init_filename @var{filename}
> Set filename to the fragment files header file, default filename is @file{init.mp4}.
> 
> +@item hls_fmp4_init_refresh @var{filename}
> +Resend init file after m3u8 file refresh every time, default is @var{0}.
> +
> When @code{var_stream_map} is set with two or more variant streams, the
> @var{filename} pattern must contain the string "%v", this string specifies
> the position of variant stream index in the generated init file names.
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index b4c72b6e54..dbf0381b75 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -119,6 +119,7 @@ typedef struct VariantStream {
>     int packets_written;
>     int init_range_length;
>     uint8_t *temp_buffer;
> +    uint8_t *init_buffer;
> 
>     AVFormatContext *avf;
>     AVFormatContext *vtt_avf;
> @@ -192,6 +193,7 @@ typedef struct HLSContext {
>     char *segment_filename;
>     char *fmp4_init_filename;
>     int segment_type;
> +    int resend_init_file;  ///< resend init file into disk after refresh m3u8
> 
>     int use_localtime;      ///< flag to expand filename with localtime
>     int use_localtime_mkdir;///< flag to mkdir dirname in timebased filename
> @@ -2234,6 +2236,23 @@ static int hls_write_header(AVFormatContext *s)
>     return ret;
> }
> 
> +static int hls_init_file_refresh(AVFormatContext *s, VariantStream *vs)
> +{
> +    HLSContext *hls = s->priv_data;
> +    AVDictionary *options = NULL;
> +    int ret = 0;
> +
> +    set_http_options(s, &options, hls);
> +    ret = hlsenc_io_open(s, &vs->out, hls->fmp4_init_filename, &options);
> +    av_dict_free(&options);
> +    if (ret < 0)
> +        return ret;
> +    avio_write(vs->out, vs->init_buffer, vs->init_range_length);
> +    hlsenc_io_close(s, &vs->out, hls->fmp4_init_filename);
> +
> +    return ret;
> +}
> +
> static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
> {
>     HLSContext *hls = s->priv_data;
> @@ -2246,7 +2265,6 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
>     int range_length = 0;
>     const char *proto = NULL;
>     int use_temp_file = 0;
> -    uint8_t *buffer = NULL;
>     VariantStream *vs = NULL;
>     char *old_filename = NULL;
> 
> @@ -2332,9 +2350,12 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
>         avio_flush(oc->pb);
>         if (hls->segment_type == SEGMENT_TYPE_FMP4) {
>             if (!vs->init_range_length) {
> -                range_length = avio_close_dyn_buf(oc->pb, &buffer);
> -                avio_write(vs->out, buffer, range_length);
> -                av_freep(&buffer);
> +                range_length = avio_close_dyn_buf(oc->pb, &vs->init_buffer);
> +                if (range_length <= 0)
> +                    return AVERROR(EINVAL);
> +                avio_write(vs->out, vs->init_buffer, range_length);
> +                if (!hls->resend_init_file)
> +                    av_freep(&vs->init_buffer);
>                 vs->init_range_length = range_length;
>                 avio_open_dyn_buf(&oc->pb);
>                 vs->packets_written = 0;
> @@ -2446,6 +2467,14 @@ static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
>             }
>         }
> 
> +        if (hls->resend_init_file && hls->segment_type == SEGMENT_TYPE_FMP4) {
> +            ret = hls_init_file_refresh(s, vs);
> +            if (ret < 0) {
> +                av_freep(&old_filename);
> +                return ret;
> +            }
> +        }
> +
>         if (hls->flags & HLS_SINGLE_FILE) {
>             vs->number++;
>             vs->start_pos += vs->size;
> @@ -2510,7 +2539,8 @@ static void hls_free_variant_streams(struct HLSContext *hls)
>         }
> 
>         avformat_free_context(vs->avf);
> -
> +        if (hls->resend_init_file)
> +            av_freep(&vs->init_buffer);
>         hls_free_segments(vs->segments);
>         hls_free_segments(vs->old_segments);
>         av_freep(&vs->m3u8_name);
> @@ -3010,6 +3040,7 @@ static const AVOption options[] = {
>     {"mpegts",   "make segment file to mpegts files in m3u8", 0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_TYPE_MPEGTS }, 0, UINT_MAX,   E, "segment_type"},
>     {"fmp4",   "make segment file to fragment mp4 files in m3u8", 0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_TYPE_FMP4 }, 0, UINT_MAX,   E, "segment_type"},
>     {"hls_fmp4_init_filename", "set fragment mp4 file init filename", OFFSET(fmp4_init_filename),   AV_OPT_TYPE_STRING, {.str = "init.mp4"},            0,       0,         E},
> +    {"hls_fmp4_init_resend", "resend fragment mp4 init file after refresh m3u8 every time", OFFSET(resend_init_file), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
>     {"hls_flags",     "set flags affecting HLS playlist and media file generation", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0 }, 0, UINT_MAX, E, "flags"},
>     {"single_file",   "generate a single media file indexed with byte ranges", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_SINGLE_FILE }, 0, UINT_MAX,   E, "flags"},
>     {"temp_file", "write segment and playlist to temporary file and rename when complete", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_TEMP_FILE }, 0, UINT_MAX,   E, "flags"},
> -- 
> 2.25.0
> 

Thanks

Steven Liu