[FFmpeg-devel] [PATCH] options_table: replace INT64_MAX with a sligthly smaller value

[Michael Niedermayer]

On Fri, Nov 18, 2016 at 11:06:56PM +0100, Andreas Cadhalpun wrote:
> AVOption.max is a double, which has not enough precision for INT64_MAX.
> 
> It gets interpreted as INT64_MIN, when converted back to int64_t.
> 
> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
> ---
>  libavcodec/options_table.h | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/libavcodec/options_table.h b/libavcodec/options_table.h
> index 48de667..f117ce4 100644
> --- a/libavcodec/options_table.h
> +++ b/libavcodec/options_table.h
> @@ -41,8 +41,10 @@
>  
>  #define AV_CODEC_DEFAULT_BITRATE 200*1000
>  
> +#define FF_INT64_MAX (INT64_MAX - 0x1000)

Missing documentation


> +
>  static const AVOption avcodec_options[] = {
> -{"b", "set bitrate (in bits/s)", OFFSET(bit_rate), AV_OPT_TYPE_INT64, {.i64 = AV_CODEC_DEFAULT_BITRATE }, 0, INT64_MAX, A|V|E},
> +{"b", "set bitrate (in bits/s)", OFFSET(bit_rate), AV_OPT_TYPE_INT64, {.i64 = AV_CODEC_DEFAULT_BITRATE }, 0, FF_INT64_MAX, A|V|E},
>  {"ab", "set bitrate (in bits/s)", OFFSET(bit_rate), AV_OPT_TYPE_INT64, {.i64 = 128*1000 }, 0, INT_MAX, A|E},
>  {"bt", "Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate tolerance specifies how far "
>         "ratecontrol is willing to deviate from the target average bitrate value. This is not related "
> @@ -444,11 +446,11 @@ static const AVOption avcodec_options[] = {
>  #if FF_API_PRIVATE_OPT
>  {"min_prediction_order", NULL, OFFSET(min_prediction_order), AV_OPT_TYPE_INT, {.i64 = -1 }, INT_MIN, INT_MAX, A|E},
>  {"max_prediction_order", NULL, OFFSET(max_prediction_order), AV_OPT_TYPE_INT, {.i64 = -1 }, INT_MIN, INT_MAX, A|E},
> -{"timecode_frame_start", "GOP timecode frame start number, in non-drop-frame format", OFFSET(timecode_frame_start), AV_OPT_TYPE_INT64, {.i64 = -1 }, -1, INT64_MAX, V|E},
> +{"timecode_frame_start", "GOP timecode frame start number, in non-drop-frame format", OFFSET(timecode_frame_start), AV_OPT_TYPE_INT64, {.i64 = -1 }, -1, FF_INT64_MAX, V|E},
>  #endif

>  {"bits_per_raw_sample", NULL, OFFSET(bits_per_raw_sample), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX},
> -{"channel_layout", NULL, OFFSET(channel_layout), AV_OPT_TYPE_INT64, {.i64 = DEFAULT }, 0, INT64_MAX, A|E|D, "channel_layout"},
> +{"channel_layout", NULL, OFFSET(channel_layout), AV_OPT_TYPE_INT64, {.i64 = DEFAULT }, 0, FF_INT64_MAX, A|E|D, "channel_layout"},
> -{"request_channel_layout", NULL, OFFSET(request_channel_layout), AV_OPT_TYPE_INT64, {.i64 = DEFAULT }, 0, INT64_MAX, A|D, "request_channel_layout"},
> +{"request_channel_layout", NULL, OFFSET(request_channel_layout), AV_OPT_TYPE_INT64, {.i64 = DEFAULT }, 0, FF_INT64_MAX, A|D, "request_channel_layout"},

this doesnt feel right
layout is not a scalar

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Awnsering whenever a program halts or runs forever is
On a turing machine, in general impossible (turings halting problem).
On any real computer, always possible as a real computer has a finite number
of states N, and will either halt in less than N cycles or never halt.
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