[FFmpeg-devel,v3,2/3] avformat/mov: add support for 'amve' ambient viewing environment box. As defined in ISOBMFF (ISO/IEC 14496-12) document.

From: Damiano Galassi <damiog@gmail.com>

Co-Authored-By: Cosmin Stejerean <cosmin@cosmin.at>
---
 libavformat/dump.c   | 15 +++++++++++++++
 libavformat/isom.h   |  3 +++
 libavformat/mov.c    | 35 +++++++++++++++++++++++++++++++++++
 libavformat/movenc.c | 30 ++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+)

On 2/4/2024 8:16 AM, Cosmin Stejerean via ffmpeg-devel wrote:
> From: Damiano Galassi <damiog@gmail.com>
> 
> Co-Authored-By: Cosmin Stejerean <cosmin@cosmin.at>
> ---
>   libavformat/dump.c   | 15 +++++++++++++++
>   libavformat/isom.h   |  3 +++
>   libavformat/mov.c    | 35 +++++++++++++++++++++++++++++++++++
>   libavformat/movenc.c | 30 ++++++++++++++++++++++++++++++
>   4 files changed, 83 insertions(+)
> 
> diff --git a/libavformat/dump.c b/libavformat/dump.c
> index aff51b43f6..add38914f2 100644
> --- a/libavformat/dump.c
> +++ b/libavformat/dump.c
> @@ -28,6 +28,7 @@
>   #include "libavutil/intreadwrite.h"
>   #include "libavutil/log.h"
>   #include "libavutil/mastering_display_metadata.h"
> +#include "libavutil/ambient_viewing_environment.h"
>   #include "libavutil/dovi_meta.h"
>   #include "libavutil/mathematics.h"
>   #include "libavutil/opt.h"
> @@ -379,6 +380,17 @@ static void dump_content_light_metadata(void *ctx, const AVPacketSideData *sd,
>              metadata->MaxCLL, metadata->MaxFALL);
>   }
>   
> +static void dump_ambient_viewing_environment_metadata(void *ctx, const AVPacketSideData *sd)
> +{
> +    const AVAmbientViewingEnvironment *ambient =
> +        (const AVAmbientViewingEnvironment *)sd->data;
> +    av_log(ctx, AV_LOG_INFO, "Ambient Viewing Environment, "
> +           "ambient_illuminance=%f, ambient_light_x=%f, ambient_light_y=%f",
> +           av_q2d(ambient->ambient_illuminance),
> +           av_q2d(ambient->ambient_light_x),
> +           av_q2d(ambient->ambient_light_y));
> +}
> +
>   static void dump_spherical(void *ctx, const AVCodecParameters *par,
>                              const AVPacketSideData *sd, int log_level)
>   {
> @@ -513,6 +525,9 @@ static void dump_sidedata(void *ctx, const AVStream *st, const char *indent,
>               av_log(ctx, log_level, "SMPTE ST 12-1:2014: ");
>               dump_s12m_timecode(ctx, st, sd, log_level);
>               break;
> +        case AV_PKT_DATA_AMBIENT_VIEWING_ENVIRONMENT:
> +            dump_ambient_viewing_environment_metadata(ctx, sd);
> +            break;
>           default:
>               av_log(ctx, log_level, "unknown side data type %d "
>                      "(%"SIZE_SPECIFIER" bytes)", sd->type, sd->size);
> diff --git a/libavformat/isom.h b/libavformat/isom.h
> index 77221d06e4..a4cca4c798 100644
> --- a/libavformat/isom.h
> +++ b/libavformat/isom.h
> @@ -29,6 +29,7 @@
>   
>   #include "libavutil/encryption_info.h"
>   #include "libavutil/mastering_display_metadata.h"
> +#include "libavutil/ambient_viewing_environment.h"
>   #include "libavutil/spherical.h"
>   #include "libavutil/stereo3d.h"
>   
> @@ -249,6 +250,8 @@ typedef struct MOVStreamContext {
>       AVMasteringDisplayMetadata *mastering;
>       AVContentLightMetadata *coll;
>       size_t coll_size;
> +    AVAmbientViewingEnvironment *ambient;
> +    size_t ambient_size;
>   
>       uint32_t format;
>   
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 5fae777adb..42b0135987 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -6039,6 +6039,31 @@ static int mov_read_clli(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>       return 0;
>   }
>   
> +static int mov_read_amve(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> +{
> +    MOVStreamContext *sc;
> +    const int illuminance_den = 10000;
> +    const int ambient_den = 50000;
> +    if (c->fc->nb_streams < 1)
> +        return AVERROR_INVALIDDATA;
> +    sc = c->fc->streams[c->fc->nb_streams - 1]->priv_data;
> +    if (atom.size < 6) {
> +        av_log(c->fc, AV_LOG_ERROR, "Empty Ambient Viewing Environment Info box\n");
> +        return AVERROR_INVALIDDATA;
> +    }
> +    if (sc->ambient){
> +        av_log(c->fc, AV_LOG_WARNING, "Ignoring duplicate AMVE\n");
> +        return 0;
> +    }
> +    sc->ambient = av_ambient_viewing_environment_alloc(&sc->ambient_size);
> +    if (!sc->ambient)
> +        return AVERROR(ENOMEM);
> +    sc->ambient->ambient_illuminance  = av_make_q(avio_rb32(pb), illuminance_den);
> +    sc->ambient->ambient_light_x = av_make_q(avio_rb16(pb), ambient_den);
> +    sc->ambient->ambient_light_y = av_make_q(avio_rb16(pb), ambient_den);
> +    return 0;
> +}
> +
>   static int mov_read_st3d(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>   {
>       AVStream *st;
> @@ -8215,6 +8240,7 @@ static const MOVParseTableEntry mov_default_parse_table[] = {
>   { MKTAG('i','s','p','e'), mov_read_ispe },
>   { MKTAG('i','p','r','p'), mov_read_iprp },
>   { MKTAG('i','i','n','f'), mov_read_iinf },
> +{ MKTAG('a','m','v','e'), mov_read_amve }, /* ambient viewing environment box */
>   { 0, NULL }
>   };
>   
> @@ -8680,6 +8706,7 @@ static void mov_free_stream_context(AVFormatContext *s, AVStream *st)
>       av_freep(&sc->spherical);
>       av_freep(&sc->mastering);
>       av_freep(&sc->coll);
> +    av_freep(&sc->ambient);
>   }
>   
>   static int mov_read_close(AVFormatContext *s)
> @@ -9072,6 +9099,14 @@ static int mov_read_header(AVFormatContext *s)
>   
>                   sc->coll = NULL;
>               }
> +            if (sc->ambient) {
> +                if (!av_packet_side_data_add(&st->codecpar->coded_side_data, &st->codecpar->nb_coded_side_data,
> +                                             AV_PKT_DATA_AMBIENT_VIEWING_ENVIRONMENT,
> +                                             (uint8_t *) sc->ambient, sc->ambient_size, 0))
> +                    return AVERROR(ENOMEM);
> +
> +                sc->ambient = NULL;
> +            }
>               break;
>           }
>       }
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index b724bd5ebc..c2410e01ce 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -2244,6 +2244,35 @@ static int mov_write_mdcv_tag(AVIOContext *pb, MOVTrack *track)
>       return 32;
>   }
>   
> +static int mov_write_amve_tag(AVIOContext *pb, MOVTrack *track)
> +{
> +    const int illuminance_den = 10000;
> +    const int ambient_den = 50000;
> +    const AVPacketSideData *side_data;
> +    const AVAmbientViewingEnvironment *ambient;
> +
> +
> +    side_data = av_packet_side_data_get(track->st->codecpar->coded_side_data,
> +                                                              track->st->codecpar->nb_coded_side_data,
> +                                                              AV_PKT_DATA_AMBIENT_VIEWING_ENVIRONMENT);

Excessive indentation.

> +
> +    if (!side_data || !side_data->data) {
> +        return 0;
> +    }

Don't use brackets if it's a single line.

> +
> +    ambient = (const AVAmbientViewingEnvironment*)side_data->data;
> +    if (!ambient || !ambient->ambient_illuminance.num) {
> +        return 0;
> +    }

Ditto.

> +
> +    avio_wb32(pb, 16); // size
> +    ffio_wfourcc(pb, "amve");
> +    avio_wb32(pb, rescale_mdcv(ambient->ambient_illuminance, illuminance_den));

nit: Maybe rename rescale_mdcv() to something more descriptive now that 
it's not just used by mdcv?

> +    avio_wb16(pb, rescale_mdcv(ambient->ambient_light_x, ambient_den));
> +    avio_wb16(pb, rescale_mdcv(ambient->ambient_light_y, ambient_den));
> +    return 16;
> +}
> +
>   static void find_compressor(char * compressor_name, int len, MOVTrack *track)
>   {
>       AVDictionaryEntry *encoder;
> @@ -2457,6 +2486,7 @@ static int mov_write_video_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContex
>       if (track->mode == MODE_MOV || track->mode == MODE_MP4) {
>           mov_write_clli_tag(pb, track);
>           mov_write_mdcv_tag(pb, track);
> +        mov_write_amve_tag(pb, track);
>       }
>   
>       if (track->mode == MODE_MP4 && mov->fc->strict_std_compliance <= FF_COMPLIANCE_UNOFFICIAL) {