From: Gyan Doshi <ffmpeg@gyani.pro> To: ffmpeg-devel@ffmpeg.org Subject: Re: [FFmpeg-devel] [PATCH 1/2] avformat: add avformat_query_seekable Date: Mon, 14 Apr 2025 09:53:42 +0530 Message-ID: <60e25c6d-22ac-45d1-8946-0178f5f84071@gyani.pro> (raw) In-Reply-To: <DM8P223MB03651EDCA0D837A06C6B7C62BAB02@DM8P223MB0365.NAMP223.PROD.OUTLOOK.COM> On 2025-04-13 09:39 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 1/2] avformat: add >> avformat_query_seekable >> >> Utility function to report seekability features for a given input. >> >> Useful for ffprobe and to extend seek possibilities in fftools. >> --- >> doc/APIchanges | 3 +++ >> libavformat/avformat.h | 22 ++++++++++++++++++ >> libavformat/seek.c | 53 ++++++++++++++++++++++++++++++++++++++++++ >> libavformat/version.h | 2 +- >> 4 files changed, 79 insertions(+), 1 deletion(-) >> >> diff --git a/doc/APIchanges b/doc/APIchanges >> index 65bf5a9419..879f56b572 100644 >> --- a/doc/APIchanges >> +++ b/doc/APIchanges >> @@ -2,6 +2,9 @@ The last version increases of all libraries were on >> 2025-03-28 >> >> API changes, most recent first: >> >> +2025-04-xx - xxxxxxxxxx - lavf 62.1.100 - avformat.h >> + Add avformat_query_seekable(). >> + >> 2025-04-07 - 19e9a203b7 - lavu 60.01.100 - dict.h >> Add AV_DICT_DEDUP. >> >> diff --git a/libavformat/avformat.h b/libavformat/avformat.h >> index 498c3020a5..e00f1ed0d9 100644 >> --- a/libavformat/avformat.h >> +++ b/libavformat/avformat.h >> @@ -2338,6 +2338,28 @@ int av_seek_frame(AVFormatContext *s, int >> stream_index, int64_t timestamp, >> */ >> int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t >> min_ts, int64_t ts, int64_t max_ts, int flags); > Hi Gyan, > > I like the idea of showing seekability in FFprobe output! > > As far as I understand, these flags are expressing three different things: > > > 1. Seek method > >> +#define AVSEEKABLE_NORMAL 0x01 ///< I/O is seekable like a local >> file >> +#define AVSEEKABLE_PROTOCOL 0x02 ///< I/O seek is through protocol >> request via avio_seek_time >> +#define AVSEEKABLE_DEMUXER 0x04 ///< demuxer has a seek function >> +#define AVSEEKABLE_PKTSCAN 0x08 ///< seek is performed by consuming The first is not a method. It indicates whether the input is streamed. > 2. Seek parameter type > >> and scanning packet timestamps >> +#define AVSEEKABLE_TIME 0x10 ///< seek target can be a timestamp >> +#define AVSEEKABLE_BYTE 0x20 ///< seek target can be in bytes >> +#define AVSEEKABLE_FRAME 0x40 ///< seek target can be a frame >> index > 3. Additional seek behavior > >> +#define AVSEEKABLE_PTS 0x100 ///< seek target timestamp is >> expected to be PTS >> +#define AVSEEKABLE_FAST 0x200 ///< demuxer allows fast but >> inaccurate seeking >> +#define AVSEEKABLE_FWDONLY 0x400 ///< set seek will be equal or >> forward of specified seek point > > Wouldn't it be better for clarity when this differentiation would be > reflected in the naming? > > Maybe something like this: > > AVSEEKABLE_VIA_DEMUXER > > AVSEEKABLE_BY_TIME > > AVSEEKABLE_BEHAVIOR_FAST Will do. > Another note: > >> +#define AVSEEKABLE_NORMAL 0x01 ///< I/O is seekable like a local >> +#define AVSEEKABLE_PROTOCOL 0x02 ///< I/O seek is through protocol >> +#define AVSEEKABLE_DEMUXER 0x04 ///< demuxer has a seek function >> +#define AVSEEKABLE_PKTSCAN 0x08 ///< seek is performed by consuming > There's no (numeric) room for extending the first block At the moment, there are 21 unused bits so there's no need as such. > >> +#define AVSEEKABLE_TIME 0x10 ///< seek target can be a timestamp >> +#define AVSEEKABLE_BYTE 0x20 ///< seek target can be in bytes >> +#define AVSEEKABLE_FRAME 0x40 ///< seek target can be a frame > >> + // TODO: no flag for frame seeking. Add flag and update this check >> + if (s->iformat->flags & 0) >> + ret |= AVSEEKABLE_FRAME; >> + >> + if (s->iformat->flags & AVFMT_SEEK_TO_PTS) >> + ret |= AVSEEKABLE_PTS; > Maybe add a check for AVSEEKABLE_TIME - for sanity? Only a handful of demuxers have this flag, and all have TS. This is a job for reviewers when adding the flag. > >> + // TODO: flag exists but not added to the demuxers which support it >> + if (s->iformat->flags & AVFMT_FLAG_FAST_SEEK) >> + ret |= AVSEEKABLE_FAST; > > > Another idea would be to return a struct (like AVSeekability) with a clear > separation of those three types of information, maybe that would provide > better clarity? As alluded above, there's only a handful of attributes being indicated. I'd rather not spawn a new type when an inbuilt simple storage type will do. Regards, Gyan _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
next prev parent reply other threads:[~2025-04-14 4:23 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2025-04-13 11:15 Gyan Doshi 2025-04-13 11:15 ` [FFmpeg-devel] [PATCH 2/2] ffprobe: show seekability details in format section Gyan Doshi 2025-04-13 16:18 ` softworkz . 2025-04-14 4:39 ` Gyan Doshi 2025-04-14 4:52 ` softworkz . 2025-04-14 4:57 ` softworkz . 2025-04-14 6:53 ` Gyan Doshi 2025-04-14 7:27 ` softworkz . 2025-04-14 10:36 ` Gyan Doshi 2025-04-14 8:34 ` Nicolas George 2025-04-13 16:09 ` [FFmpeg-devel] [PATCH 1/2] avformat: add avformat_query_seekable softworkz . 2025-04-14 4:23 ` Gyan Doshi [this message] 2025-04-14 4:40 ` softworkz . 2025-04-13 16:42 ` Zhao Zhili 2025-04-14 4:10 ` Gyan Doshi
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