[FFmpeg-devel] dash: add descriptor which is useful to the scheme defined by ISO/IEC 23009-1:2014/Amd.2:2015.

[Jeyapal, Karthick]

On 7/19/19 1:13 PM, leozhang wrote:
> Signed-off-by: leozhang <leozhang at qiyi.com>
> ---
> Removed remarks which are not part of commit message. Thanks reminder
>
>  doc/muxers.texi       |  4 ++++
>  libavformat/dashenc.c | 27 +++++++++++++++++++++++----
>  2 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index b109297..bc38cf6 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -275,6 +275,10 @@ of the adaptation sets and a,b,c,d and e are the indices of the mapped streams.
>  To map all video (or audio) streams to an AdaptationSet, "v" (or "a") can be used as stream identifier instead of IDs.
>  
>  When no assignment is defined, this defaults to an AdaptationSet for each stream.
> +
> +Optional syntax is "id=x,descriptor=descriptor_string,streams=a,b,c id=y,streams=d,e" and so on, descriptor is useful to the scheme defined by ISO/IEC 23009-1:2014/Amd.2:2015.
> +For example, -adaptation_sets "id=0,descriptor=<SupplementalProperty schemeIdUri=\"urn:mpeg:dash:srd:2014\" value=\"0,0,0,1,1,2,2\"/>,streams=v".
> +Please note that descriptor string should be a self-closing xml tag.
>  @item timeout @var{timeout}
>  Set timeout for socket I/O operations. Applicable only for HTTP output.
>  @item index_correction @var{index_correction}
> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> index b25afb4..24f8d4d 100644
> --- a/libavformat/dashenc.c
> +++ b/libavformat/dashenc.c
> @@ -68,6 +68,7 @@ typedef struct Segment {
>  
>  typedef struct AdaptationSet {
>      char id[10];
> +    char *descriptor;
>      enum AVMediaType media_type;
>      AVDictionary *metadata;
>      AVRational min_frame_rate, max_frame_rate;
> @@ -552,8 +553,10 @@ static void dash_free(AVFormatContext *s)
>      int i, j;
>  
>      if (c->as) {
> -        for (i = 0; i < c->nb_as; i++)
> +        for (i = 0; i < c->nb_as; i++) {
>              av_dict_free(&c->as[i].metadata);
> +            av_freep(&c->as[i].descriptor);
> +        }
>          av_freep(&c->as);
>          c->nb_as = 0;
>      }
> @@ -748,7 +751,8 @@ static int write_adaptation_set(AVFormatContext *s, AVIOContext *out, int as_ind
>      role = av_dict_get(as->metadata, "role", NULL, 0);
>      if (role)
>          avio_printf(out, "\t\t\t<Role schemeIdUri=\"urn:mpeg:dash:role:2011\" value=\"%s\"/>\n", role->value);
> -
> +    if (as->descriptor)
> +        avio_printf(out, "\t\t\t%s\n", as->descriptor);
>      for (i = 0; i < s->nb_streams; i++) {
>          OutputStream *os = &c->streams[i];
>          char bandwidth_str[64] = {'\0'};
> @@ -820,7 +824,7 @@ static int parse_adaptation_sets(AVFormatContext *s)
>  {
>      DASHContext *c = s->priv_data;
>      const char *p = c->adaptation_sets;
> -    enum { new_set, parse_id, parsing_streams } state;
> +    enum { new_set, parse_id, parsing_streams, parse_descriptor } state;
>      AdaptationSet *as;
>      int i, n, ret;
>  
> @@ -837,6 +841,9 @@ static int parse_adaptation_sets(AVFormatContext *s)
>      }
>  
>      // syntax id=0,streams=0,1,2 id=1,streams=3,4 and so on
> +    // option id=0,descriptor=descriptor_str,streams=0,1,2 and so on
> +    // descriptor is useful to the scheme defined by ISO/IEC 23009-1:2014/Amd.2:2015
> +    // descriptor_str should be a self-closing xml tag.
>      state = new_set;
>      while (*p) {
>          if (*p == ' ') {
> @@ -854,7 +861,19 @@ static int parse_adaptation_sets(AVFormatContext *s)
>              if (*p)
>                  p++;
>              state = parse_id;
> -        } else if (state == parse_id && av_strstart(p, "streams=", &p)) {
> +        } else if (state == parse_id && av_strstart(p, "descriptor=", &p)) {
> +            n = strcspn(p, ">") + 1; //followed by one comma, so plus 1
> +            if (n < strlen(p)) {
> +                as->descriptor = av_strndup(p, n);
> +            } else {
> +                av_log(s, AV_LOG_ERROR, "Parse error, descriptor string should be a self-closing xml tag\n");
> +                return AVERROR(EINVAL);
> +            }
> +            p += n;
> +            if (*p)
> +                p++;
> +            state = parse_descriptor;
> +        } else if ((state == parse_id || state == parse_descriptor) && av_strstart(p, "streams=", &p)) { //descriptor is optional 
>              state = parsing_streams;
>          } else if (state == parsing_streams) {
>              AdaptationSet *as = &c->as[c->nb_as - 1];

Pushed, with minor change to commit message and removing a trailing space.

Regards,
Karthick