[FFmpeg-devel] [PATCH 2/5] avformat/dovi_isom: implement dv_md_compression

[Cosmin Stejerean]

> On Jul 16, 2024, at 1:23 PM, Niklas Haas <ffmpeg at haasn.xyz> wrote:
> 
> From: Niklas Haas <git at haasn.dev>
> 
> ---
> libavformat/dovi_isom.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/libavformat/dovi_isom.c b/libavformat/dovi_isom.c
> index d49aa5a75f..269374cff9 100644
> --- a/libavformat/dovi_isom.c
> +++ b/libavformat/dovi_isom.c
> @@ -57,11 +57,14 @@ int ff_isom_parse_dvcc_dvvc(void *logctx, AVStream *st,
> 
>     // Has enough remaining data
>     if (size >= 5) {
> -        dovi->dv_bl_signal_compatibility_id = ((*buf_ptr++) >> 4) & 0x0f; // 4 bits
> +        uint8_t buf = *buf_ptr++;
> +        dovi->dv_bl_signal_compatibility_id = (buf >> 4) & 0x0f; // 4 bits
> +        dovi->dv_md_compression = (buf >> 2) & 0x03; // 2 bits

This seems fine based on what this code is currently doing, but I'm curious, should this be moved to something like get_bits at some point?

>     } else {
>         // 0 stands for None
>         // Dolby Vision V1.2.93 profiles and levels
>         dovi->dv_bl_signal_compatibility_id = 0;
> +        dovi->dv_md_compression = AV_DOVI_COMPRESSION_NONE;
>     }
> 
>     if (!av_packet_side_data_add(&st->codecpar->coded_side_data, &st->codecpar->nb_coded_side_data,
> @@ -71,13 +74,14 @@ int ff_isom_parse_dvcc_dvvc(void *logctx, AVStream *st,
>     }
> 
>     av_log(logctx, AV_LOG_TRACE, "DOVI in dvcC/dvvC/dvwC box, version: %d.%d, profile: %d, level: %d, "
> -           "rpu flag: %d, el flag: %d, bl flag: %d, compatibility id: %d\n",
> +           "rpu flag: %d, el flag: %d, bl flag: %d, compatibility id: %d, compression: %d\n",
>            dovi->dv_version_major, dovi->dv_version_minor,
>            dovi->dv_profile, dovi->dv_level,
>            dovi->rpu_present_flag,
>            dovi->el_present_flag,
>            dovi->bl_present_flag,
> -           dovi->dv_bl_signal_compatibility_id);
> +           dovi->dv_bl_signal_compatibility_id,
> +           dovi->dv_md_compression);
> 
>     return 0;
> }
> @@ -97,8 +101,9 @@ void ff_isom_put_dvcc_dvvc(void *logctx, uint8_t out[ISOM_DVCC_DVVC_SIZE],
>     put_bits(&pb, 1, !!dovi->el_present_flag);
>     put_bits(&pb, 1, !!dovi->bl_present_flag);
>     put_bits(&pb, 4, dovi->dv_bl_signal_compatibility_id & 0x0f);
> +    put_bits(&pb, 2, dovi->dv_md_compression & 0x03);
> 
> -    put_bits(&pb, 28, 0); /* reserved */
> +    put_bits(&pb, 26, 0); /* reserved */
>     put_bits32(&pb, 0); /* reserved */
>     put_bits32(&pb, 0); /* reserved */
>     put_bits32(&pb, 0); /* reserved */
> @@ -108,12 +113,14 @@ void ff_isom_put_dvcc_dvvc(void *logctx, uint8_t out[ISOM_DVCC_DVVC_SIZE],
> 
>     av_log(logctx, AV_LOG_DEBUG,
>            "DOVI in %s box, version: %d.%d, profile: %d, level: %d, "
> -           "rpu flag: %d, el flag: %d, bl flag: %d, compatibility id: %d\n",
> +           "rpu flag: %d, el flag: %d, bl flag: %d, compatibility id: %d, "
> +           "compression: %d\n",

would it be more user friendly to log the display value like limited, none, extended rather than numeric value here?

>            dovi->dv_profile > 10 ? "dvwC" : (dovi->dv_profile > 7 ? "dvvC" : "dvcC"),
>            dovi->dv_version_major, dovi->dv_version_minor,
>            dovi->dv_profile, dovi->dv_level,
>            dovi->rpu_present_flag,
>            dovi->el_present_flag,
>            dovi->bl_present_flag,
> -           dovi->dv_bl_signal_compatibility_id);
> +           dovi->dv_bl_signal_compatibility_id,
> +           dovi->dv_md_compression);
> }
> -- 
> 

Overall LGTM.

- Cosmin