[FFmpeg-devel] [PATCH 1/3 v2] avformat/apetag: fix flag value to signal footer presence

[Paul B Mahol]

On 2/10/17, James Almer <jamrial at gmail.com> wrote:
> According to the spec[1], a value of 0 means the footer is present and a
> value
> of 1 means it's absent, the exact opposite of header presence flag where 1
> means present and 0 absent.
> The reason for this is compatibility with APEv1 tags, where there's no
> header,
> footer presence was mandatory for all files, and the flags field was a
> zeroed
> reserved field.
>
> [1] http://wiki.hydrogenaud.io/index.php?title=Ape_Tags_Flags
>
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
> v2 changes: Added missing fate test update.
>
> Files already created are obviously wrong, but fortunately having the flag
> mistakenly reporting there's no footer is harmless in APEv2 tags stored at
> the end of the file (The only kind we can read and write), since footer is
> mandatory in those and no and such software really bothers looking at the
> flag.
>
> I renamed the constant just to have it as reference, or until someone feels
> like adding support for APEv2 tags at the beginning of a file, where footer
> becomes optional.
>
>  libavformat/apetag.c | 7 +++----
>  tests/ref/lavf/tta   | 2 +-
>  2 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/libavformat/apetag.c b/libavformat/apetag.c
> index 08e80f4aa3..a05b32d9e5 100644
> --- a/libavformat/apetag.c
> +++ b/libavformat/apetag.c
> @@ -30,7 +30,7 @@
>  #include "internal.h"
>
>  #define APE_TAG_FLAG_CONTAINS_HEADER  (1 << 31)
> -#define APE_TAG_FLAG_CONTAINS_FOOTER  (1 << 30)
> +#define APE_TAG_FLAG_LACKS_FOOTER     (1 << 30)
>  #define APE_TAG_FLAG_IS_HEADER        (1 << 29)
>  #define APE_TAG_FLAG_IS_BINARY        (1 << 1)
>
> @@ -189,8 +189,7 @@ int ff_ape_write_tag(AVFormatContext *s)
>          goto end;
>
>      // flags
> -    avio_wl32(dyn_bc, APE_TAG_FLAG_CONTAINS_HEADER |
> APE_TAG_FLAG_CONTAINS_FOOTER |
> -                     APE_TAG_FLAG_IS_HEADER);
> +    avio_wl32(dyn_bc, APE_TAG_FLAG_CONTAINS_HEADER |
> APE_TAG_FLAG_IS_HEADER);
>      ffio_fill(dyn_bc, 0, 8);             // reserved
>
>      ff_standardize_creation_time(s);
> @@ -232,7 +231,7 @@ int ff_ape_write_tag(AVFormatContext *s)
>      avio_wl32(s->pb, count);            // tag count
>
>      // flags
> -    avio_wl32(s->pb, APE_TAG_FLAG_CONTAINS_HEADER |
> APE_TAG_FLAG_CONTAINS_FOOTER);
> +    avio_wl32(s->pb, APE_TAG_FLAG_CONTAINS_HEADER);
>      ffio_fill(s->pb, 0, 8);             // reserved
>
>  end:
> diff --git a/tests/ref/lavf/tta b/tests/ref/lavf/tta
> index 745e8d21bd..d86d097e3d 100644
> --- a/tests/ref/lavf/tta
> +++ b/tests/ref/lavf/tta
> @@ -1,3 +1,3 @@
> -f2721d06704ac43d89fdd25835b43598 *./tests/data/lavf/lavf.tta
> +d86c5cccb2554143d34d1786ab460a31 *./tests/data/lavf/lavf.tta
>  43200 ./tests/data/lavf/lavf.tta
>  ./tests/data/lavf/lavf.tta CRC=0x3a1da17e
> --
> 2.11.0
>
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>

probably ok