[FFmpeg-devel] [PATCH 2/4] API: add AV_PKT_DATA_S12M_TIMECODE to AVPacketSideDataType
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Mon Jun 29 16:52:00 EEST 2020
lance.lmwang at gmail.com:
> On Mon, Jun 29, 2020 at 02:06:49PM +0200, Andreas Rheinhardt wrote:
>> lance.lmwang at gmail.com:
>>> On Mon, Jun 29, 2020 at 04:53:21AM +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 | 8 ++++++++
>>>>> libavcodec/version.h | 2 +-
>>>>> libavformat/dump.c | 22 ++++++++++++++++++++++
>>>>> 6 files changed, 36 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..a4316a7 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 12-1 timecode";
>>>>> }
>>>>> return NULL;
>>>>> }
>>>>> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
>>>>> index a4e50c0..a2bf0cc 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 41485f4..72cb4f7 100644
>>>>> --- a/libavcodec/packet.h
>>>>> +++ b/libavcodec/packet.h
>>>>> @@ -283,6 +283,14 @@ enum AVPacketSideDataType {
>>>>> AV_PKT_DATA_DOVI_CONF,
>>>>>
>>>>> /**
>>>>> + * Timecode which conforms to SMPTE ST 12-1. 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.
>>>>> + * The timecode format is described in the av_timecode_get_smpte_from_framenum()
>>>>> + * function in libavutil/timecode.c.
>>>>
>>>> The format is documented in a C source file, not a public header? Sure
>>>> about that?
>>>
>>> For AV_PKT_DATA_S12M_TIMECODE use the same format with AV_FRAME_DATA_S12M_TIMECODE, so I copy the
>>> comments for AV_FRAME_DATA_S12M_TIMECODE, it's not my comments for it. I think the format is described
>>> in "SMPTE ST 12-2:2014" standard document, but it's not free for download.
>>>
>>
>> It's SMPTE ST 12-1:2014 and this standard is currently (until 21 July)
>> available for free [1] due to Corona.
>
> oh, it's good to hear it's free due to Corona. I haven't notice it's online.
>
>>
>>> What's your suggestion to change?
>>>
>>
>> The best is probably to incorporate the documentation of the format into
>> the documentation of av_timecode_get_smpte_from_framenum.
> OK, I'll remove the comments for the timecode format.
>>
>>>>
>>>>> + */
>>>>> + 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..c5f0bd6 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 +403,23 @@ static void dump_dovi_conf(void *ctx, AVPacketSideData* sd)
>>>>> dovi->dv_bl_signal_compatibility_id);
>>>>> }
>>>>>
>>>>> +static void dump_s12m_timecode(void *ctx, AVPacketSideData* sd)
>>>>> +{
>>>>> + uint32_t *tc = (uint32_t*)sd->data;
>>>>> + int m = tc[0] & 3;
>>>>> +
>>>>> + if (sd->size != sizeof(uint32_t) * 4) {
>>
>> You already dereferenced tc before this check which might crash if the
>> size is actually < sizeof(uint32_t). And why do you only look at the
>> lowest two bits of m? Is this designed with future extensions of the
>> timecode in mind? But even then one can't simply use the upper 30 bits
>> to store something else, because that has not been documented.
>> (Moreover, if one allowed extensions, one should allow sd->size to be >=
>> sizeof(uint32_t) * 4.)
>
> It's from the comments for the side data, it used to avoid index overflow,
> for the array is 4. I'll fix to get the m after the checking.
I know it is to ensure that you don't overread. I'd simply consider it
invalid data if the count were > 3.
>
> comments:
> where the first uint32_t describes how many (1-3) of the other timecodes are used
>
> I think it's for the timecode SEI define 2bits for the count of used timecomes,
> it's not related to SMPTE ST 12-1. vf_showinfo.c have dump AV_FRAME_DATA_S12M_TIMECODE,
> I'm following it as format is same, but change m to & 3 for I think it's more simple.
>
>
>>
>>>>> + av_log(ctx, AV_LOG_ERROR, "invalid data");
>>>>> + return;
>>>>> + }
>>>>> +
>>>>> + for (int j = 1; j <= m; 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 != m ? ", " : "");
>>>>> + }
>>>>> +}
>>>>> +
>>
>> - Andreas
>>
>> [1]: https://www.smpte.org/free-standards-and-publications
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