Re: [FFmpeg-devel] [PATCH 2/2] ffprobe: show seekability details in format section

["softworkz ." <softworkz-at-hotmail.com@ffmpeg.org>]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces@ffmpeg.org> On Behalf Of Gyan
> Doshi
> Sent: Montag, 14. April 2025 06:40
> To: ffmpeg-devel@ffmpeg.org
> Subject: Re: [FFmpeg-devel] [PATCH 2/2] ffprobe: show seekability
> details in format section
> 
> 
> 
> On 2025-04-13 09:48 pm, softworkz . wrote:
> >
> >> -----Original Message-----
> >> From: ffmpeg-devel<ffmpeg-devel-bounces@ffmpeg.org>  On Behalf Of
> Gyan
> >> Doshi
> >> Sent: Sonntag, 13. April 2025 13:16
> >> To:ffmpeg-devel@ffmpeg.org
> >> Subject: [FFmpeg-devel] [PATCH 2/2] ffprobe: show seekability details
> in
> >> format section
> >>
> >> ---
> >>   fftools/ffprobe.c                    | 49
> +++++++++++++++++++++++++++-
> >>   tests/ref/fate/cavs-demux            |  2 +-
> >>   tests/ref/fate/ffprobe_compact       |  2 +-
> >>   tests/ref/fate/ffprobe_csv           |  2 +-
> >>   tests/ref/fate/ffprobe_default       |  1 +
> >>   tests/ref/fate/ffprobe_flat          |  1 +
> >>   tests/ref/fate/ffprobe_ini           |  1 +
> >>   tests/ref/fate/ffprobe_json          |  1 +
> >>   tests/ref/fate/ffprobe_xml           |  2 +-
> >>   tests/ref/fate/ffprobe_xsd           |  2 +-
> >>   tests/ref/fate/flv-demux             |  2 +-
> >>   tests/ref/fate/gapless-mp3-side-data |  2 +-
> >>   tests/ref/fate/oggopus-demux         |  2 +-
> >>   tests/ref/fate/ts-demux              |  2 +-
> >>   tests/ref/fate/ts-opus-demux         |  2 +-
> >>   tests/ref/fate/ts-small-demux        |  2 +-
> >>   tests/ref/fate/ts-timed-id3-demux    |  2 +-
> >>   17 files changed, 64 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/fftools/ffprobe.c b/fftools/ffprobe.c
> >> index e0a7322523..8b09afb8c1 100644
> >> --- a/fftools/ffprobe.c
> >> +++ b/fftools/ffprobe.c
> >> @@ -2260,7 +2260,7 @@ static int show_format(AVTextFormatContext
> *tfc,
> >> InputFile *ifile)
> >>   {
> >>       AVFormatContext *fmt_ctx = ifile->fmt_ctx;
> >>       int64_t size = fmt_ctx->pb ? avio_size(fmt_ctx->pb) : -1;
> >> -    int ret = 0;
> >> +    int seekable, ret = 0;
> >>
> >>       avtext_print_section_header(tfc, NULL, SECTION_ID_FORMAT);
> >>       print_str_validate("filename", fmt_ctx->url);
> >> @@ -2279,6 +2279,53 @@ static int show_format(AVTextFormatContext
> *tfc,
> >> InputFile *ifile)
> >>       if (fmt_ctx->bit_rate > 0) print_val    ("bit_rate", fmt_ctx-
> >>> bit_rate, unit_bit_per_second_str);
> >>       else                       print_str_opt("bit_rate", "N/A");
> >>       print_int("probe_score", fmt_ctx->probe_score);
> >> +
> >> +    seekable = avformat_query_seekable(fmt_ctx);
> >> +    if (seekable > 0) {
> >> +        int gen = 1, ante = 0;
> >> +        AVBPrint seek_str;
> >> +        av_bprint_init(&seek_str, 0, AV_BPRINT_SIZE_AUTOMATIC);
> >> +
> >> +        av_bprintf(&seek_str, "yes, by");
> >> +        if (seekable & AVSEEKABLE_TIME) {
> >> +            av_bprintf(&seek_str, " time");
> >> +            if (seekable & AVSEEKABLE_PTS)
> >> +                av_bprintf(&seek_str, "(pts)");
> >> +            else
> >> +                av_bprintf(&seek_str, "(dts)");
> >> +            ante = 1;
> >> +        }
> >> +        if (seekable & AVSEEKABLE_BYTE) {
> >> +            av_bprintf(&seek_str, "%cbyte-offset", ante ? ',':' ');
> >> +            ante = 1;
> >> +        }
> >> +        if (seekable & AVSEEKABLE_FRAME) {
> >> +            av_bprintf(&seek_str, "%cframe-index", ante ? ',':' ');
> >> +        }
> >> +
> >> +        ante = 0;
> >> +        av_bprintf(&seek_str, " via");
> >> +        if (seekable & AVSEEKABLE_DEMUXER) {
> >> +            av_bprintf(&seek_str, " demuxer");
> >> +            gen = 0;
> >> +            ante = 1;
> >> +        }
> >> +        if (seekable & AVSEEKABLE_PKTSCAN) {
> >> +            av_bprintf(&seek_str, "%cpacket-scan", ante ? ',':' ');
> >> +            gen = 0;
> >> +            ante = 0;
> >> +        }
> >> +        if (gen)
> >> +            av_bprintf(&seek_str, " generic seek");
> >> +
> >> +        if (seekable & AVSEEKABLE_FWDONLY)
> >> +            av_bprintf(&seek_str, " (forward only)");
> >> +
> >> +        print_str("seekable",      seek_str.str);
> >> +    }
> >> +    else
> >> +        print_str("seekable",      "no");
> >> +
> >>       if (do_show_format_tags)
> >>           ret = show_tags(tfc, fmt_ctx->metadata,
> >> SECTION_ID_FORMAT_TAGS);
> >
> > Hi Gyan,
> >
> > the problem that I see here is that it's not machine-readable and
> would require non-trivial parsing to translate back to the actual
> information behind it.
> > I think that either a separate sub-section or at least three separate
> values would be better.
> 
> I can add a delimiter like |
> 
> e.g.
> 
> yes|time(pts),frame-index|demuxer,packet-scan|fast
> 
> All of the phrases for an attribute are unique, and for that, they just
> need to grep, not parse the string.
> Most CLI users will only care about two things: yes/no and forward-only.

When processing data using formats like XML or JSON by software, there is no "grep".
Machine-readable means (not only but including) that no additional parsing needs to be done. The XML schema must indicate the possible values and I don't believe that a pipe-delimited multi-string value can be described with an XML schema.

Best,
sw



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