lance.lmw...@gmail.com: > On Sun, Jul 12, 2020 at 03:07:18AM +0200, Andreas Rheinhardt wrote: >> lance.lmw...@gmail.com: >>> From: Limin Wang <lance.lmw...@gmail.com> >>> >>> Signed-off-by: Limin Wang <lance.lmw...@gmail.com> >>> --- >>> libavdevice/decklink_dec.cpp | 14 ++++++++++++++ >>> 1 file changed, 14 insertions(+) >>> >>> diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp >>> index a499972..146f56f 100644 >>> --- a/libavdevice/decklink_dec.cpp >>> +++ b/libavdevice/decklink_dec.cpp >>> @@ -42,6 +42,7 @@ extern "C" { >>> #include "libavutil/imgutils.h" >>> #include "libavutil/intreadwrite.h" >>> #include "libavutil/time.h" >>> +#include "libavutil/timecode.h" >>> #include "libavutil/mathematics.h" >>> #include "libavutil/reverse.h" >>> #include "avdevice.h" >>> @@ -882,6 +883,19 @@ HRESULT >>> decklink_input_callback::VideoInputFrameArrived( >>> AVDictionary* metadata_dict = NULL; >>> int metadata_len; >>> uint8_t* packed_metadata; >>> + AVTimecode tcr; >>> + >>> + if (av_timecode_init_from_string(&tcr, >>> ctx->video_st->r_frame_rate, tc, ctx) >= 0) { >>> + uint32_t tc_data = >>> av_timecode_get_smpte_from_framenum(&tcr, 0); >>> + int size = sizeof(uint32_t) * 4; >>> + uint8_t *sd = av_packet_new_side_data(&pkt, >>> AV_PKT_DATA_S12M_TIMECODE, size); >>> + >>> + if (sd) { >>> + AV_WL32(sd, 1); // one TC ; >> >> Nit: why is there a space after TC? > > Will remove it, it's not intentional. > >> >>> + AV_WL32(sd + 4, tc_data); // TC; >> >> This contradicts the documentation of AV_PKT_DATA_S12M_TIMECODE, because >> you are always using little endian here. But the documentation [1] does >> not specify an endianness, it uses native endianness (in accordance with >> what AV_FRAME_DATA_S12M_TIMECODE does). This very same patch also uses >> native endianness in libavformat/dump.c. > > good catch, at first, I think it's little endian order, and Nicolas comment > uint32_t is native, so I remove the commens for the byte order. I'll change > to use AV_WB32() for native write. >
AV_WB uses big-endian. Instead you could simply use an uint32_t* to write the numbers. >> >> I consider it a mistake to use native endianness for the frame side data >> and an uint32_t in av_timecode_get_smpte (none of the fields cross a >> byte boundary, so each entry could easily have been an uint8_t[4]), as >> this will make it harder to test this side data via fate; but I also see >> the advantage of using the same format and the same helper functions for >> both. What do others think about this? After all, we can still change >> the format for the packet side data. > > I didn't get the SMPTE S314M:2005 specs for checking, it's not free. I think > use native format is fine for local system, but if the side data is packed > into > or read from specific format like DV, AV_WB32() and AV_RB32() had to be used. > For the fate testing, I think we can't test the side data binary only, if > needed, > we can test the format which use the sidedata like dv. The framecrc muxer calculates a checksum of every side data. There is already a special way of calculating the side-data for palettes in big-endian and it seems that we can simply reuse this (as both are based on uint32_t in native format). So it seems it won't be much of a problem. - Andreas _______________________________________________ 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".