[FFmpeg-devel] [RFC][PATCH] Windows Television (WTV) file system handling

[Ronald S. Bultje]

Hi Peter,

On Thu, Jan 20, 2011 at 12:19 AM, Peter Ross <pross at xvid.org> wrote:
> On Sun, Jan 09, 2011 at 05:21:20PM +1100, Peter Ross wrote:
>> 0002-add-AVFMT_NOGENERICSEEK-flag.patch
>> * adds AVFMT_NOGENERICSEEK flag, which should be self explanatory.
[..]
> @@ -23,7 +23,7 @@
>
>  #define LIBAVFORMAT_VERSION_MAJOR 52
>  #define LIBAVFORMAT_VERSION_MINOR 92
> -#define LIBAVFORMAT_VERSION_MICRO  0
> +#define LIBAVFORMAT_VERSION_MICRO  1
>
>  #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>                                                 LIBAVFORMAT_VERSION_MINOR, \
> @@ -324,6 +324,7 @@ typedef struct AVFormatParameters {
>  #define AVFMT_VARIABLE_FPS  0x0400 /**< Format allows variable fps. */
>  #define AVFMT_NODIMENSIONS  0x0800 /**< Format does not need width/height */
>  #define AVFMT_NOSTREAMS     0x1000 /**< Format does not require any streams */
> +#define AVFMT_NOGENERICSEEK 0x2000 /**< Do not perform generic read_seek */
>
>  typedef struct AVOutputFormat {
>      const char *name;
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> index 32067e9..365272b 100644
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -1747,6 +1747,9 @@ int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int f
>          return 0;
>      }
>
> +    if ((s->iformat->flags & AVFMT_NOGENERICSEEK))
> +        return -1;
> +
>      if(s->iformat->read_timestamp)
>          return av_seek_frame_binary(s, stream_index, timestamp, flags);
>      else

What does this do/fix?

>> 0001-make-unicode-string-reader-accessible-to-other-modu.patch
>> * the metadata format uses unicode structures similar, but not identical,
>> ? to ASF/DRV-MS.
[..]
>  /**
> + * Read a null terminated string
> + */
> +static void get_utf16z(ByteIOContext *pb, char *buf, int buf_size)
> +{
> +    char* q = buf;
> +    int ch;
> +    while ((ch = get_le16(pb)))
> +        if (q - buf < buf_size - 1) *q++ = ch;
> +    *q = '\0';
> +}

Already exists in asfdec.c, probably, and likely mms uses that one
also. Can you reuse that function? It looks ok in general, I think
we'd want some files in this format in fate so this sort of stuff is
tested.

> +static const ff_asf_guid dir_entry_guid =
> +    {0x92,0xb7,0x74,0x91,0x59,0x70,0x70,0x44,0x88,0xdf,0x06,0x3b,0x82,0xcc,0x21,0x3d};

Should it be in the asf header? Seems duplicated.

> +/**
> + * @param[in] buf unicode buffer
> + * @param buf_size buffer size (bytes)
> + * @return 0 if equal
> + */
> +static int unicode_compare(const uint8_t *buf, int buf_size, const uint8_t *s)

I'd be shocked if libc didn't provide some way of doing this, convert
utf16->utf8 and then strcmp()? Also you don't check buf[i*2+1] ever, I
know people always make fun of MS using UTF16 and then keeping every
second byte as a NULL, but it's possible that it is _not_ NULL, right?

Ronald