Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Thu, 11 Apr 2024 00:09:05 +0200 Michael Niedermayer wrote: > On Mon, Apr 08, 2024 at 11:55:02PM +0200, Niklas Haas wrote: > > On Mon, 08 Apr 2024 22:18:33 +0200 Michael Niedermayer > > wrote: > > > On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > > > > From: Niklas Haas > > > > > > > > This replaces the myriad of existing lists in AVCodec by a unified API > > > > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > > > > substantially, while also making this more trivially extensible. > > > > > > > > In addition to the already covered lists, add two new entries for color > > > > space and color range, mirroring the newly added negotiable fields in > > > > libavfilter. > > > > > > > > I decided to drop the explicit length field from the API proposed by > > > > Andreas Rheinhardt, because having it in place ended up complicating > > > > both the codec side and the client side implementations, while also > > > > being strictly less flexible (it's trivial to recover a length given > > > > a terminator, but requires allocation to add a terminator given > > > > a length). Using a terminator also presents less of a porting challenge > > > > for existing users of the current API. > > > > > > > > Once the deprecation period passes for the existing public fields, the > > > > rough plan is to move the commonly used fields (such as > > > > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > > > > configuration types, and then implement the rarely used fields with > > > > custom callbacks. > > > > --- > > > > doc/APIchanges | 5 > > > > libavcodec/avcodec.c| 51 + > > > > libavcodec/avcodec.h| 27 > > > > libavcodec/codec.h | 19 +++--- > > > > libavcodec/codec_internal.h | 21 +++ > > > > libavcodec/version.h| 4 +-- > > > > 6 files changed, 121 insertions(+), 6 deletions(-) > > > > > > This patchset seems to overlap a bit with AVOptionRanges > > > > > > I think ideally the user should at some point be able to query using some > > > API on a AVCodecContext/AVCodecParameters/AVFormatContex/AVStream > > > what for that specific instance are supported settings for each field > > > > > > The API here seems to use a enum, which can make sense but it differs from > > > how AVOption works which doesnt use enums to identify fields > > > > I didn't know AVOptionRanges exists; indeed it can be seen as somewhat > > overlapping here. That said, there is a vital distinction here: > > AVOptionRanges > > represents *static* limits on what options can be set (e.g. via > > `av_opt_set_int`), whereas this API represents *dynamic* limits on what can > > be > > coded. > > AVOptionRanges where definitly not intended to be static > > see the docs: > * The returned list may depend on other fields in obj like for example > profile. > > that would not be static > > > > > > > In particular, the list of supported colorspaces etc. can *depend* on the > > value > > of other options. Currently, only strict_std_compliance, but I can easily > > see > > this list growing in the future (e.g. for different profiles, dolbyvision, > > ...). > > > > That aside, I personally find an API based on strings and doubles rather > > cumbersome to use, especially when downstream clients expect an enum list. > > AVOption* is intended to be a generic API. > For example something that an App can query to build a drop down menu in a GUI > for each parameter > > For this, it must be possible to iterate over all paremeters, then for each > iterate over all possible settings if its a discrete type or range if its a > continous type. And then present the user with the corresponding GUI elements > > thx Okay, then I do not present as strong an objection as I thought. That said, I still think that downstream API users will be very thankful for having a replacement API that's easy to migrate to, rather one that's IMO rather difficult to use (and which requires both FPU and malloc to access what used to be just a static list). What do other people think? Should we introduce this new API as-is, or should it be scrapped in favor of reusing AVOptionRanges? ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Mon, Apr 08, 2024 at 11:55:02PM +0200, Niklas Haas wrote: > On Mon, 08 Apr 2024 22:18:33 +0200 Michael Niedermayer > wrote: > > On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > > > From: Niklas Haas > > > > > > This replaces the myriad of existing lists in AVCodec by a unified API > > > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > > > substantially, while also making this more trivially extensible. > > > > > > In addition to the already covered lists, add two new entries for color > > > space and color range, mirroring the newly added negotiable fields in > > > libavfilter. > > > > > > I decided to drop the explicit length field from the API proposed by > > > Andreas Rheinhardt, because having it in place ended up complicating > > > both the codec side and the client side implementations, while also > > > being strictly less flexible (it's trivial to recover a length given > > > a terminator, but requires allocation to add a terminator given > > > a length). Using a terminator also presents less of a porting challenge > > > for existing users of the current API. > > > > > > Once the deprecation period passes for the existing public fields, the > > > rough plan is to move the commonly used fields (such as > > > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > > > configuration types, and then implement the rarely used fields with > > > custom callbacks. > > > --- > > > doc/APIchanges | 5 > > > libavcodec/avcodec.c| 51 + > > > libavcodec/avcodec.h| 27 > > > libavcodec/codec.h | 19 +++--- > > > libavcodec/codec_internal.h | 21 +++ > > > libavcodec/version.h| 4 +-- > > > 6 files changed, 121 insertions(+), 6 deletions(-) > > > > This patchset seems to overlap a bit with AVOptionRanges > > > > I think ideally the user should at some point be able to query using some > > API on a AVCodecContext/AVCodecParameters/AVFormatContex/AVStream > > what for that specific instance are supported settings for each field > > > > The API here seems to use a enum, which can make sense but it differs from > > how AVOption works which doesnt use enums to identify fields > > I didn't know AVOptionRanges exists; indeed it can be seen as somewhat > overlapping here. That said, there is a vital distinction here: AVOptionRanges > represents *static* limits on what options can be set (e.g. via > `av_opt_set_int`), whereas this API represents *dynamic* limits on what can be > coded. AVOptionRanges where definitly not intended to be static see the docs: * The returned list may depend on other fields in obj like for example profile. that would not be static > > In particular, the list of supported colorspaces etc. can *depend* on the > value > of other options. Currently, only strict_std_compliance, but I can easily see > this list growing in the future (e.g. for different profiles, dolbyvision, > ...). > > That aside, I personally find an API based on strings and doubles rather > cumbersome to use, especially when downstream clients expect an enum list. AVOption* is intended to be a generic API. For example something that an App can query to build a drop down menu in a GUI for each parameter For this, it must be possible to iterate over all paremeters, then for each iterate over all possible settings if its a discrete type or range if its a continous type. And then present the user with the corresponding GUI elements thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Does the universe only have a finite lifespan? No, its going to go on forever, its just that you wont like living in it. -- Hiranya Peiri signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Mon, 08 Apr 2024 22:18:33 +0200 Michael Niedermayer wrote: > On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > > From: Niklas Haas > > > > This replaces the myriad of existing lists in AVCodec by a unified API > > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > > substantially, while also making this more trivially extensible. > > > > In addition to the already covered lists, add two new entries for color > > space and color range, mirroring the newly added negotiable fields in > > libavfilter. > > > > I decided to drop the explicit length field from the API proposed by > > Andreas Rheinhardt, because having it in place ended up complicating > > both the codec side and the client side implementations, while also > > being strictly less flexible (it's trivial to recover a length given > > a terminator, but requires allocation to add a terminator given > > a length). Using a terminator also presents less of a porting challenge > > for existing users of the current API. > > > > Once the deprecation period passes for the existing public fields, the > > rough plan is to move the commonly used fields (such as > > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > > configuration types, and then implement the rarely used fields with > > custom callbacks. > > --- > > doc/APIchanges | 5 > > libavcodec/avcodec.c| 51 + > > libavcodec/avcodec.h| 27 > > libavcodec/codec.h | 19 +++--- > > libavcodec/codec_internal.h | 21 +++ > > libavcodec/version.h| 4 +-- > > 6 files changed, 121 insertions(+), 6 deletions(-) > > This patchset seems to overlap a bit with AVOptionRanges > > I think ideally the user should at some point be able to query using some > API on a AVCodecContext/AVCodecParameters/AVFormatContex/AVStream > what for that specific instance are supported settings for each field > > The API here seems to use a enum, which can make sense but it differs from > how AVOption works which doesnt use enums to identify fields I didn't know AVOptionRanges exists; indeed it can be seen as somewhat overlapping here. That said, there is a vital distinction here: AVOptionRanges represents *static* limits on what options can be set (e.g. via `av_opt_set_int`), whereas this API represents *dynamic* limits on what can be coded. In particular, the list of supported colorspaces etc. can *depend* on the value of other options. Currently, only strict_std_compliance, but I can easily see this list growing in the future (e.g. for different profiles, dolbyvision, ...). That aside, I personally find an API based on strings and doubles rather cumbersome to use, especially when downstream clients expect an enum list. > > > [...] > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > Never trust a computer, one day, it may think you are the virus. -- Compn > ___ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Mon, Apr 08, 2024 at 10:18:33PM +0200, Michael Niedermayer wrote: > On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > > From: Niklas Haas > > > > This replaces the myriad of existing lists in AVCodec by a unified API > > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > > substantially, while also making this more trivially extensible. > > > > In addition to the already covered lists, add two new entries for color > > space and color range, mirroring the newly added negotiable fields in > > libavfilter. > > > > I decided to drop the explicit length field from the API proposed by > > Andreas Rheinhardt, because having it in place ended up complicating > > both the codec side and the client side implementations, while also > > being strictly less flexible (it's trivial to recover a length given > > a terminator, but requires allocation to add a terminator given > > a length). Using a terminator also presents less of a porting challenge > > for existing users of the current API. > > > > Once the deprecation period passes for the existing public fields, the > > rough plan is to move the commonly used fields (such as > > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > > configuration types, and then implement the rarely used fields with > > custom callbacks. > > --- > > doc/APIchanges | 5 > > libavcodec/avcodec.c| 51 + > > libavcodec/avcodec.h| 27 > > libavcodec/codec.h | 19 +++--- > > libavcodec/codec_internal.h | 21 +++ > > libavcodec/version.h| 4 +-- > > 6 files changed, 121 insertions(+), 6 deletions(-) > > This patchset seems to overlap a bit with AVOptionRanges > > I think ideally the user should at some point be able to query using some > API on a AVCodecContext/AVCodecParameters/AVFormatContex/AVStream > what for that specific instance are supported settings for each field let me clarify this a bit more, what i envission is some generic API that can take any AVClass/AVOption suporting struct and query a instance of it for supported ranges/lists of a AVOption field. some AVCodec passed into that call in addition to a AVCodecContext would be more messy in a generic API thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB No great genius has ever existed without some touch of madness. -- Aristotle signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > From: Niklas Haas > > This replaces the myriad of existing lists in AVCodec by a unified API > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > substantially, while also making this more trivially extensible. > > In addition to the already covered lists, add two new entries for color > space and color range, mirroring the newly added negotiable fields in > libavfilter. > > I decided to drop the explicit length field from the API proposed by > Andreas Rheinhardt, because having it in place ended up complicating > both the codec side and the client side implementations, while also > being strictly less flexible (it's trivial to recover a length given > a terminator, but requires allocation to add a terminator given > a length). Using a terminator also presents less of a porting challenge > for existing users of the current API. > > Once the deprecation period passes for the existing public fields, the > rough plan is to move the commonly used fields (such as > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > configuration types, and then implement the rarely used fields with > custom callbacks. > --- > doc/APIchanges | 5 > libavcodec/avcodec.c| 51 + > libavcodec/avcodec.h| 27 > libavcodec/codec.h | 19 +++--- > libavcodec/codec_internal.h | 21 +++ > libavcodec/version.h| 4 +-- > 6 files changed, 121 insertions(+), 6 deletions(-) This patchset seems to overlap a bit with AVOptionRanges I think ideally the user should at some point be able to query using some API on a AVCodecContext/AVCodecParameters/AVFormatContex/AVStream what for that specific instance are supported settings for each field The API here seems to use a enum, which can make sense but it differs from how AVOption works which doesnt use enums to identify fields [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Never trust a computer, one day, it may think you are the virus. -- Compn signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Sun, 07 Apr 2024 01:16:39 +0200 Michael Niedermayer wrote: > On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > > From: Niklas Haas > > > > This replaces the myriad of existing lists in AVCodec by a unified API > > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > > substantially, while also making this more trivially extensible. > > > > In addition to the already covered lists, add two new entries for color > > space and color range, mirroring the newly added negotiable fields in > > libavfilter. > > > > I decided to drop the explicit length field from the API proposed by > > Andreas Rheinhardt, because having it in place ended up complicating > > both the codec side and the client side implementations, while also > > being strictly less flexible (it's trivial to recover a length given > > a terminator, but requires allocation to add a terminator given > > a length). Using a terminator also presents less of a porting challenge > > for existing users of the current API. > > > > Once the deprecation period passes for the existing public fields, the > > rough plan is to move the commonly used fields (such as > > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > > configuration types, and then implement the rarely used fields with > > custom callbacks. > > --- > > doc/APIchanges | 5 > > libavcodec/avcodec.c| 51 + > > libavcodec/avcodec.h| 27 > > libavcodec/codec.h | 19 +++--- > > libavcodec/codec_internal.h | 21 +++ > > libavcodec/version.h| 4 +-- > > 6 files changed, 121 insertions(+), 6 deletions(-) > > If the API is changed, it should be to an API that allows externally > maintained codecs. > (it would result in more developers working on codecs) The only way this could work is by making all of FFCodec public, which is orthogonal to the API proposed here. > > thx > > [...] > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > it is not once nor twice but times without number that the same ideas make > their appearance in the world. -- Aristotle > ___ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
Quoting Michael Niedermayer (2024-04-07 01:16:39) > On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > > From: Niklas Haas > > > > This replaces the myriad of existing lists in AVCodec by a unified API > > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > > substantially, while also making this more trivially extensible. > > > > In addition to the already covered lists, add two new entries for color > > space and color range, mirroring the newly added negotiable fields in > > libavfilter. > > > > I decided to drop the explicit length field from the API proposed by > > Andreas Rheinhardt, because having it in place ended up complicating > > both the codec side and the client side implementations, while also > > being strictly less flexible (it's trivial to recover a length given > > a terminator, but requires allocation to add a terminator given > > a length). Using a terminator also presents less of a porting challenge > > for existing users of the current API. > > > > Once the deprecation period passes for the existing public fields, the > > rough plan is to move the commonly used fields (such as > > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > > configuration types, and then implement the rarely used fields with > > custom callbacks. > > --- > > doc/APIchanges | 5 > > libavcodec/avcodec.c| 51 + > > libavcodec/avcodec.h| 27 > > libavcodec/codec.h | 19 +++--- > > libavcodec/codec_internal.h | 21 +++ > > libavcodec/version.h| 4 +-- > > 6 files changed, 121 insertions(+), 6 deletions(-) > > If the API is changed, it should be to an API that allows externally > maintained codecs. > (it would result in more developers working on codecs) This seems like a complete non sequitur in relation to this patch. -- Anton Khirnov ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Fri, Apr 05, 2024 at 08:57:11PM +0200, Niklas Haas wrote: > From: Niklas Haas > > This replaces the myriad of existing lists in AVCodec by a unified API > call, allowing us to (ultimately) trim down the sizeof(AVCodec) quite > substantially, while also making this more trivially extensible. > > In addition to the already covered lists, add two new entries for color > space and color range, mirroring the newly added negotiable fields in > libavfilter. > > I decided to drop the explicit length field from the API proposed by > Andreas Rheinhardt, because having it in place ended up complicating > both the codec side and the client side implementations, while also > being strictly less flexible (it's trivial to recover a length given > a terminator, but requires allocation to add a terminator given > a length). Using a terminator also presents less of a porting challenge > for existing users of the current API. > > Once the deprecation period passes for the existing public fields, the > rough plan is to move the commonly used fields (such as > pix_fmt/sample_fmt) into FFCodec, possibly as a union of audio and video > configuration types, and then implement the rarely used fields with > custom callbacks. > --- > doc/APIchanges | 5 > libavcodec/avcodec.c| 51 + > libavcodec/avcodec.h| 27 > libavcodec/codec.h | 19 +++--- > libavcodec/codec_internal.h | 21 +++ > libavcodec/version.h| 4 +-- > 6 files changed, 121 insertions(+), 6 deletions(-) If the API is changed, it should be to an API that allows externally maintained codecs. (it would result in more developers working on codecs) thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB it is not once nor twice but times without number that the same ideas make their appearance in the world. -- Aristotle signature.asc Description: PGP signature ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
Re: [FFmpeg-devel] [PATCH 01/11] avcodec: add avcodec_get_supported_config()
On Fri, 05 Apr 2024 20:57:11 +0200 Niklas Haas wrote: > From: Niklas Haas > In addition to the already covered lists, add two new entries for color > space and color range, mirroring the newly added negotiable fields in > libavfilter. If this passes review, I will submit a second series implementing these new fields for relevant codecs. ___ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
