[FFmpeg-devel] [PATCH 1/2] lavf: add info_probe_size option.

[Stefano Sabatini]

On date Monday 2012-04-23 14:02:40 +0200, Nicolas George encoded:
> This option separates the "probe format" and "probe packets
> for various info" semantic of the probesize option.
> Input formats are now allowed to raise it if necessary under
> special circumstances (example: large rawvideo frames).
> 
> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> ---
>  libavformat/avformat.h      |    6 ++++++
>  libavformat/options_table.h |    1 +
>  libavformat/utils.c         |    8 +++++---
>  libavformat/version.h       |    2 +-
>  4 files changed, 13 insertions(+), 4 deletions(-)
> 
> 

> I originally added a more lengthy documentation in avoptions_format.texi but
> it was overwritten. I did not find where to put it.

If you want my opinion that would be an hand-written file
libavformat.texi, but that would require much maintainance work and
possible desynching.

Another problem of the print_options.c approach is that it is
specifying avconv syntax (in documentation geared towards library
usage).

> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index d2727d4..f6850bc 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -1016,6 +1016,12 @@ typedef struct AVFormatContext {
>      AVIOInterruptCB interrupt_callback;
>  
>      /**
> +     * decoding: size of data to probe for stream information;

Nit: "for getting streams information"?

> +     * encoding: unused.
> +     */
> +    unsigned int info_probe_size;

Bickering: would be "stream_info_probe_size" or "stream_probe_size"
more suited?

Also maybe "stream_info_probesize", consistent with probesize.
Also as Michael noted move this to the end of the struct.

> +
> +    /**
>       * Flags to enable debugging.
>       */
>      int debug;
> diff --git a/libavformat/options_table.h b/libavformat/options_table.h
> index 8d57c27..0cf2680 100644
> --- a/libavformat/options_table.h
> +++ b/libavformat/options_table.h
> @@ -64,6 +64,7 @@ static const AVOption options[]={
>  {"careful",    "consider things that violate the spec and have not been seen in the wild as errors", 0, AV_OPT_TYPE_CONST, {.dbl = AV_EF_CAREFUL }, INT_MIN, INT_MAX, D, "err_detect"},
>  {"compliant",  "consider all spec non compliancies as errors", 0, AV_OPT_TYPE_CONST, {.dbl = AV_EF_COMPLIANT }, INT_MIN, INT_MAX, D, "err_detect"},
>  {"aggressive", "consider things that a sane encoder shouldnt do as an error", 0, AV_OPT_TYPE_CONST, {.dbl = AV_EF_AGGRESSIVE }, INT_MIN, INT_MAX, D, "err_detect"},
> +{"info_probe_size", "maximum size to probe for stream info", OFFSET(info_probe_size), AV_OPT_TYPE_INT, {.dbl = 0}, 0, INT_MAX-1, D},

Nit: an help text tells what the option does, not what its parameter
is, so that should be "set the maximum size of data to probe...".

>  {NULL},
>  };
>  
> diff --git a/libavformat/utils.c b/libavformat/utils.c
> index de0cb54..b33e086 100644
> --- a/libavformat/utils.c
> +++ b/libavformat/utils.c
> @@ -2471,6 +2471,8 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
>          ic->streams[i]->info->last_dts = AV_NOPTS_VALUE;
>      }
>  
> +    if (!ic->info_probe_size)
> +        ic->info_probe_size = ic->probesize;
>      count = 0;
>      read_size = 0;
>      for(;;) {
> @@ -2519,15 +2521,15 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
>              }
>          }
>          /* we did not get all the codec info, but we read too much data */
> -        if (read_size >= ic->probesize) {
> +        if (read_size >= ic->info_probe_size) {
>              ret = count;
> -            av_log(ic, AV_LOG_DEBUG, "Probe buffer size limit %d reached\n", ic->probesize);
> +            av_log(ic, AV_LOG_DEBUG, "Stream info probe buffer size limit %d reached\n", ic->info_probe_size);
>              for (i = 0; i < ic->nb_streams; i++)
>                  if (!ic->streams[i]->r_frame_rate.num &&
>                      ic->streams[i]->info->duration_count <= 1)
>                      av_log(ic, AV_LOG_WARNING,
>                             "Stream #%d: not enough frames to estimate rate; "
> -                           "consider increasing probesize\n", i);
> +                           "consider increasing info_probe_size\n", i);
>              break;
>          }

Thanks for working on this (I actually *need* this patchset).
-- 
FFmpeg = Fundamental and Faithful Multimedia Perfectionist Egregious Gnome