[FFmpeg-devel] [PATCH 1/5] avformat/matroskadec: Parse Block Additional Mapping elements

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Thu Sep 23 03:55:42 EEST 2021


quietvoid:
> Most of the implementation was done by the Plex developers.
> 
> Signed-off-by: quietvoid <tcChlisop0 at gmail.com>
> ---
>  libavformat/matroska.h    |  7 ++++++
>  libavformat/matroskadec.c | 45 +++++++++++++++++++++++++++++++++++++--
>  2 files changed, 50 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/matroska.h b/libavformat/matroska.h
> index 2d04a6838b..4b2a3310a4 100644
> --- a/libavformat/matroska.h
> +++ b/libavformat/matroska.h
> @@ -111,6 +111,7 @@
>  #define MATROSKA_ID_TRACKCONTENTENCODING 0x6240
>  #define MATROSKA_ID_TRACKTIMECODESCALE 0x23314F
>  #define MATROSKA_ID_TRACKMAXBLKADDID 0x55EE
> +#define MATROSKA_ID_TRACKBLKADDMAPPING 0x41E4
>  
>  /* IDs in the trackvideo master */
>  #define MATROSKA_ID_VIDEOFRAMERATE 0x2383E3
> @@ -189,6 +190,12 @@
>  #define MATROSKA_ID_ENCODINGSIGKEYID 0x47E4
>  #define MATROSKA_ID_ENCODINGSIGNATURE 0x47E3
>  
> +/* IDs in the block addition mapping master */
> +#define MATROSKA_ID_BLKADDIDVALUE 0x41F0
> +#define MATROSKA_ID_BLKADDIDNAME 0x41A4
> +#define MATROSKA_ID_BLKADDIDTYPE 0x41E7
> +#define MATROSKA_ID_BLKADDIDEXTRADATA 0x41ED
> +
>  /* ID in the cues master */
>  #define MATROSKA_ID_POINTENTRY 0xBB
>  
> diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
> index 500c83ac3a..8ae553953d 100644
> --- a/libavformat/matroskadec.c
> +++ b/libavformat/matroskadec.c
> @@ -239,6 +239,13 @@ typedef struct MatroskaTrackOperation {
>      EbmlList combine_planes;
>  } MatroskaTrackOperation;
>  
> +typedef struct MatroskaBlockAdditionMapping {
> +    int value;
> +    char *name;
> +    int type;

This is wrong and won't work on big endian systems: Our EBML_UINT always
expects a target element of type uint64_t.

> +    EbmlBin extradata;
> +} MatroskaBlockAdditionMapping;
> +
>  typedef struct MatroskaTrack {
>      uint64_t num;
>      uint64_t uid;
> @@ -269,6 +276,7 @@ typedef struct MatroskaTrack {
>      int ms_compat;
>      int needs_decoding;
>      uint64_t max_block_additional_id;
> +    EbmlList block_addition_mappings;
>  
>      uint32_t palette[AVPALETTE_COUNT];
>      int has_palette;
> @@ -419,8 +427,8 @@ typedef struct MatroskaDemuxContext {
>  // incomplete type (6.7.2 in C90, 6.9.2 in C99).
>  // Removing the sizes breaks MSVC.
>  static EbmlSyntax ebml_syntax[3], matroska_segment[9], matroska_track_video_color[15], matroska_track_video[19],
> -                  matroska_track[32], matroska_track_encoding[6], matroska_track_encodings[2],
> -                  matroska_track_combine_planes[2], matroska_track_operation[2], matroska_tracks[2],
> +                  matroska_track[33], matroska_track_encoding[6], matroska_track_encodings[2],
> +                  matroska_track_combine_planes[2], matroska_track_operation[2], matroska_block_addition_mapping[5], matroska_tracks[2],
>                    matroska_attachments[2], matroska_chapter_entry[9], matroska_chapter[6], matroska_chapters[2],
>                    matroska_index_entry[3], matroska_index[2], matroska_tag[3], matroska_tags[2], matroska_seekhead[2],
>                    matroska_blockadditions[2], matroska_blockgroup[8], matroska_cluster_parsing[8];
> @@ -570,6 +578,14 @@ static EbmlSyntax matroska_track_operation[] = {
>      CHILD_OF(matroska_track)
>  };
>  
> +static EbmlSyntax matroska_block_addition_mapping[] = {
> +    { MATROSKA_ID_BLKADDIDVALUE,      EBML_UINT, 0, 0, offsetof(MatroskaBlockAdditionMapping, value) },
> +    { MATROSKA_ID_BLKADDIDNAME,       EBML_STR,  0, 0, offsetof(MatroskaBlockAdditionMapping, name) },
> +    { MATROSKA_ID_BLKADDIDTYPE,       EBML_UINT, 0, 0, offsetof(MatroskaBlockAdditionMapping, type) },
> +    { MATROSKA_ID_BLKADDIDEXTRADATA,  EBML_BIN,  0, 0, offsetof(MatroskaBlockAdditionMapping, extradata) },
> +    CHILD_OF(matroska_track)
> +};
> +
>  static EbmlSyntax matroska_track[] = {
>      { MATROSKA_ID_TRACKNUMBER,           EBML_UINT,  0, 0, offsetof(MatroskaTrack, num) },
>      { MATROSKA_ID_TRACKNAME,             EBML_UTF8,  0, 0, offsetof(MatroskaTrack, name) },
> @@ -593,6 +609,7 @@ static EbmlSyntax matroska_track[] = {
>      { MATROSKA_ID_TRACKOPERATION,        EBML_NEST,  0, 0, offsetof(MatroskaTrack, operation),    { .n = matroska_track_operation } },
>      { MATROSKA_ID_TRACKCONTENTENCODINGS, EBML_NEST,  0, 0, 0,                                     { .n = matroska_track_encodings } },
>      { MATROSKA_ID_TRACKMAXBLKADDID,      EBML_UINT,  0, 0, offsetof(MatroskaTrack, max_block_additional_id), { .u = 0 } },
> +    { MATROSKA_ID_TRACKBLKADDMAPPING,    EBML_NEST,  0, sizeof(MatroskaBlockAdditionMapping), offsetof(MatroskaTrack, block_addition_mappings), { .n = matroska_block_addition_mapping } },
>      { MATROSKA_ID_SEEKPREROLL,           EBML_UINT,  0, 0, offsetof(MatroskaTrack, seek_preroll), { .u = 0 } },
>      { MATROSKA_ID_TRACKFLAGENABLED,      EBML_NONE },
>      { MATROSKA_ID_TRACKFLAGLACING,       EBML_NONE },
> @@ -2306,6 +2323,26 @@ static int mkv_parse_video_projection(AVStream *st, const MatroskaTrack *track,
>      return 0;
>  }
>  
> +static int mkv_parse_block_addition_mappings(AVFormatContext *s, AVStream *st, const MatroskaTrack *track)
> +{
> +    int i, ret;
> +    const EbmlList *mappings_list = &track->block_addition_mappings;
> +    MatroskaBlockAdditionMapping *mappings = mappings_list->elem;
> +
> +    for (i = 0; i < mappings_list->nb_elem; i++) {
> +        MatroskaBlockAdditionMapping *mapping = &mappings[i];
> +
> +        switch (mapping->type) {
> +        default:
> +            av_log(s, AV_LOG_DEBUG,
> +                   "Unknown block additional mapping type %i, value %i, name \"%s\"\n",
> +                   mapping->type, mapping->value, mapping->name ? mapping->name : "");
> +        }
> +    }
> +
> +    return 0;
> +}
> +
>  static int get_qt_codec(MatroskaTrack *track, uint32_t *fourcc, enum AVCodecID *codec_id)
>  {
>      const AVCodecTag *codec_tags;
> @@ -2893,6 +2930,10 @@ static int matroska_parse_tracks(AVFormatContext *s)
>              if (track->flag_textdescriptions)
>                  st->disposition |= AV_DISPOSITION_DESCRIPTIONS;
>          }
> +
> +        ret = mkv_parse_block_addition_mappings(s, st, track);
> +        if (ret < 0)
> +            return ret;
>      }
>  
>      return 0;
> 



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