[FFmpeg-devel] [PATCH v3 1/2] API: add AV_PKT_DATA_S12M_TIMECODE to AVPacketSideDataType
lance.lmwang at gmail.com
lance.lmwang at gmail.com
Tue Jun 30 02:41:13 EEST 2020
On Mon, Jun 29, 2020 at 06:18:23PM +0200, Andreas Rheinhardt wrote:
> lance.lmwang at gmail.com:
> > On Mon, Jun 29, 2020 at 05:35:58PM +0200, Andreas Rheinhardt wrote:
> >> lance.lmwang at gmail.com:
> >>> From: Limin Wang <lance.lmwang at gmail.com>
> >>>
> >>> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> >>> ---
> >>> doc/APIchanges | 3 +++
> >>> libavcodec/avpacket.c | 1 +
> >>> libavcodec/decode.c | 1 +
> >>> libavcodec/packet.h | 6 ++++++
> >>> libavcodec/version.h | 2 +-
> >>> libavformat/dump.c | 21 +++++++++++++++++++++
> >>> 6 files changed, 33 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/doc/APIchanges b/doc/APIchanges
> >>> index 1d6cc36..7cad7fa 100644
> >>> --- a/doc/APIchanges
> >>> +++ b/doc/APIchanges
> >>> @@ -15,6 +15,9 @@ libavutil: 2017-10-21
> >>>
> >>> API changes, most recent first:
> >>>
> >>> +2020-06-xx - xxxxxxxxxx - lavc 58.94.100 - packet.h
> >>> + Add AV_PKT_DATA_S12M_TIMECODE.
> >>> +
> >>> 2020-06-12 - b09fb030c1 - lavu 56.55.100 - pixdesc.h
> >>> Add AV_PIX_FMT_X2RGB10.
> >>>
> >>> diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
> >>> index dce26cb..24e2a74 100644
> >>> --- a/libavcodec/avpacket.c
> >>> +++ b/libavcodec/avpacket.c
> >>> @@ -400,6 +400,7 @@ const char *av_packet_side_data_name(enum AVPacketSideDataType type)
> >>> case AV_PKT_DATA_PRFT: return "Producer Reference Time";
> >>> case AV_PKT_DATA_ICC_PROFILE: return "ICC Profile";
> >>> case AV_PKT_DATA_DOVI_CONF: return "DOVI configuration record";
> >>> + case AV_PKT_DATA_S12M_TIMECODE: return "SMPTE ST 12-1:2014 timecode";
> >>> }
> >>> return NULL;
> >>> }
> >>> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> >>> index de9c079..f2244fc 100644
> >>> --- a/libavcodec/decode.c
> >>> +++ b/libavcodec/decode.c
> >>> @@ -1699,6 +1699,7 @@ int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
> >>> { AV_PKT_DATA_CONTENT_LIGHT_LEVEL, AV_FRAME_DATA_CONTENT_LIGHT_LEVEL },
> >>> { AV_PKT_DATA_A53_CC, AV_FRAME_DATA_A53_CC },
> >>> { AV_PKT_DATA_ICC_PROFILE, AV_FRAME_DATA_ICC_PROFILE },
> >>> + { AV_PKT_DATA_S12M_TIMECODE, AV_FRAME_DATA_S12M_TIMECODE },
> >>> };
> >>>
> >>> if (pkt) {
> >>> diff --git a/libavcodec/packet.h b/libavcodec/packet.h
> >>> index 96f237f..d84aaaa 100644
> >>> --- a/libavcodec/packet.h
> >>> +++ b/libavcodec/packet.h
> >>> @@ -283,6 +283,12 @@ enum AVPacketSideDataType {
> >>> AV_PKT_DATA_DOVI_CONF,
> >>>
> >>> /**
> >>> + * Timecode which conforms to SMPTE ST 12-1:2014. The data is an array of 4 uint32_t
> >>> + * where the first uint32_t describes how many (1-3) of the other timecodes are used.
> >>> + */
> >>
> >> You should move the doc to timecode.h first in a separate patch and then
> >> reference the documentation here.
> >
> > I'm not native English, so it's difficult for me to describe the format of timecode in comments clearly.
> > As it's defined in SMPTE ST 12-1:2014, so I think it's enough as it says conforms to SMPTE ST 12-1:2014
> > at beginning.
> >
>
> Could you please point me to the part of SMPTE ST 12-1:2014 that
> describes the format that we use here? Because AFAIK SMPTE ST 12-1:2014
> just defines what fields a SMPTE ST 12-1 message has (and what
> semantics), but leaves the rest (the actual framing) to other standards:
>
> "The actual transport of the codewords for digital systems varies
> significantly from the transport methods defined for analog systems, and
> is defined in the associated document, SMPTE ST 12-2."
>
> E.g. RTP uses a different framing (see RFC 5484); obviously every
> framing method used for transport must prescribe endianness of not
> depend upon endianness; yet our method does. (Isn't this actually a
> problem for fate-tests because framecrc calculates checksums for side date?)
So the transport format is using SMPTE ST 12-2? I'm not sure about it. It's
better to say which standard are using in comments, it's not private format.
Now I'm just using the timecode.[ch], so it's difficult to give comments for
its format. For HEVC timecode, it's use little endianness.
>
> >>
> >>> + AV_PKT_DATA_S12M_TIMECODE,
> >>> +
> >>> + /**
> >>> * The number of side data types.
> >>> * This is not part of the public API/ABI in the sense that it may
> >>> * change when new side data types are added.
> >>> diff --git a/libavcodec/version.h b/libavcodec/version.h
> >>> index 0359302..482cc6d 100644
> >>> --- a/libavcodec/version.h
> >>> +++ b/libavcodec/version.h
> >>> @@ -28,7 +28,7 @@
> >>> #include "libavutil/version.h"
> >>>
> >>> #define LIBAVCODEC_VERSION_MAJOR 58
> >>> -#define LIBAVCODEC_VERSION_MINOR 93
> >>> +#define LIBAVCODEC_VERSION_MINOR 94
> >>> #define LIBAVCODEC_VERSION_MICRO 100
> >>>
> >>> #define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
> >>> diff --git a/libavformat/dump.c b/libavformat/dump.c
> >>> index 117c681..0f64c4f 100644
> >>> --- a/libavformat/dump.c
> >>> +++ b/libavformat/dump.c
> >>> @@ -34,6 +34,7 @@
> >>> #include "libavutil/replaygain.h"
> >>> #include "libavutil/spherical.h"
> >>> #include "libavutil/stereo3d.h"
> >>> +#include "libavutil/timecode.h"
> >>>
> >>> #include "avformat.h"
> >>>
> >>> @@ -402,6 +403,22 @@ static void dump_dovi_conf(void *ctx, AVPacketSideData* sd)
> >>> dovi->dv_bl_signal_compatibility_id);
> >>> }
> >>>
> >>> +static void dump_s12m_timecode(void *ctx, AVPacketSideData* sd)
> >>
> >> * belongs to the variable, not the type.
> >>
> >>> +{
> >>> + uint32_t *tc = (uint32_t*)sd->data;
> >>> +
> >>> + if ((sd->size != sizeof(uint32_t) * 4) || (tc[0] > 3)) {
> >>> + av_log(ctx, AV_LOG_ERROR, "invalid data\n");
> >>> + return;
> >>> + }
> >>> +
> >>> + for (int j = 1; j <= tc[0]; j++) {
> >>> + char tcbuf[AV_TIMECODE_STR_SIZE];
> >>> + av_timecode_make_smpte_tc_string(tcbuf, tc[j], 0);
> >>> + av_log(ctx, AV_LOG_INFO, "timecode - %s%s", tcbuf, j != tc[0] ? ", " : "");
> >>> + }
> >>> +}
> >>> +
> >>> static void dump_sidedata(void *ctx, AVStream *st, const char *indent)
> >>> {
> >>> int i;
> >>> @@ -468,6 +485,10 @@ static void dump_sidedata(void *ctx, AVStream *st, const char *indent)
> >>> av_log(ctx, AV_LOG_INFO, "DOVI configuration record: ");
> >>> dump_dovi_conf(ctx, &sd);
> >>> break;
> >>> + case AV_PKT_DATA_S12M_TIMECODE:
> >>> + av_log(ctx, AV_LOG_INFO, "SMPTE ST 12-1:2014: ");
> >>> + dump_s12m_timecode(ctx, &sd);
> >>> + break;
> >>> default:
> >>> av_log(ctx, AV_LOG_INFO,
> >>> "unknown side data type %d (%d bytes)", sd.type, sd.size);
> >>>
> >>
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--
Thanks,
Limin Wang
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