[FFmpeg-devel] [PATCH v2 1/4] avcodec/eac3dec: add detection of Atmos spatial extension profile
Hendrik Leppkes
h.leppkes at gmail.com
Sat Feb 18 18:45:01 EET 2023
On Sat, Feb 18, 2023 at 2:15 AM Marth64 <marth64 at proxyid.net> wrote:
>
> Signed-off-by: Marth64 <marth64 at proxyid.net>
> ---
> libavcodec/ac3dec.c | 3 +++
> libavcodec/ac3dec.h | 1 +
> libavcodec/avcodec.h | 2 ++
> libavcodec/codec_desc.c | 1 +
> libavcodec/eac3dec.c | 11 ++++++++++-
> libavcodec/profiles.c | 5 +++++
> libavcodec/profiles.h | 1 +
> 7 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
> index 0b120e6140..8cede139b8 100644
> --- a/libavcodec/ac3dec.c
> +++ b/libavcodec/ac3dec.c
> @@ -1714,6 +1714,9 @@ skip:
> if (!err) {
> avctx->sample_rate = s->sample_rate;
> avctx->bit_rate = s->bit_rate + s->prev_bit_rate;
> +
> + if (s->eac3_extension_type_a == 1)
> + avctx->profile = FF_PROFILE_EAC3_DDP_ATMOS;
> }
This should probably be something like:
avctx->profile = s->eac3_extension_type_a == 1 ?
FF_PROFILE_EAC3_DDP_ATMOS : FF_PROFILE_UNKNOWN;
This way the profile is properly reset when there is no extension (anymore).
>
> if (!avctx->sample_rate) {
> diff --git a/libavcodec/ac3dec.h b/libavcodec/ac3dec.h
> index 138b462abb..0829f4b40d 100644
> --- a/libavcodec/ac3dec.h
> +++ b/libavcodec/ac3dec.h
> @@ -102,6 +102,7 @@ typedef struct AC3DecodeContext {
> int eac3; ///< indicates if current frame is E-AC-3
> int eac3_frame_dependent_found; ///< bitstream has E-AC-3 dependent frame(s)
> int eac3_subsbtreamid_found; ///< bitstream has E-AC-3 additional substream(s)
> + int eac3_extension_type_a; ///< bitstream has E-AC-3 extension type A enabled frame(s)
> int dolby_surround_mode; ///< dolby surround mode (dsurmod)
> int dolby_surround_ex_mode; ///< dolby surround ex mode (dsurexmod)
> int dolby_headphone_mode; ///< dolby headphone mode (dheadphonmod)
> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> index 39881a1d2b..0e85dd50a4 100644
> --- a/libavcodec/avcodec.h
> +++ b/libavcodec/avcodec.h
> @@ -1591,6 +1591,8 @@ typedef struct AVCodecContext {
> #define FF_PROFILE_DTS_HD_MA 60
> #define FF_PROFILE_DTS_EXPRESS 70
>
> +#define FF_PROFILE_EAC3_DDP_ATMOS 30
> +
> #define FF_PROFILE_MPEG2_422 0
> #define FF_PROFILE_MPEG2_HIGH 1
> #define FF_PROFILE_MPEG2_SS 2
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index 199f62df15..4098d4f5a5 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -2931,6 +2931,7 @@ static const AVCodecDescriptor codec_descriptors[] = {
> .name = "eac3",
> .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
> .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
> + .profiles = NULL_IF_CONFIG_SMALL(ff_eac3_profiles),
> },
> {
> .id = AV_CODEC_ID_SIPR,
> diff --git a/libavcodec/eac3dec.c b/libavcodec/eac3dec.c
> index deca51dd3d..5c71751a0c 100644
> --- a/libavcodec/eac3dec.c
> +++ b/libavcodec/eac3dec.c
> @@ -464,7 +464,16 @@ static int ff_eac3_parse_header(AC3DecodeContext *s)
> if (get_bits1(gbc)) {
> int addbsil = get_bits(gbc, 6);
> for (i = 0; i < addbsil + 1; i++) {
> - skip_bits(gbc, 8); // skip additional bit stream info
> + if (i == 0) {
> + /* In this 8 bit chunk, the LSB is equal to flag_ec3_extension_type_a
> + which can be used to detect Atmos presence */
> + skip_bits(gbc, 7);
> + if (get_bits1(gbc)) {
> + s->eac3_extension_type_a = 1;
> + }
> + } else {
> + skip_bits(gbc, 8); // skip additional bit stream info
> + }
> }
> }
>
> diff --git a/libavcodec/profiles.c b/libavcodec/profiles.c
> index 7af7fbeb13..343b08f363 100644
> --- a/libavcodec/profiles.c
> +++ b/libavcodec/profiles.c
> @@ -45,6 +45,11 @@ const AVProfile ff_dca_profiles[] = {
> { FF_PROFILE_UNKNOWN },
> };
>
> +const AVProfile ff_eac3_profiles[] = {
> + { FF_PROFILE_EAC3_DDP_ATMOS, "Dolby Digital Plus + Dolby Atmos"},
> + { FF_PROFILE_UNKNOWN },
> +};
> +
> const AVProfile ff_dnxhd_profiles[] = {
> { FF_PROFILE_DNXHD, "DNXHD"},
> { FF_PROFILE_DNXHR_LB, "DNXHR LB"},
> diff --git a/libavcodec/profiles.h b/libavcodec/profiles.h
> index 41a19aa9ad..6ebedbd03f 100644
> --- a/libavcodec/profiles.h
> +++ b/libavcodec/profiles.h
> @@ -58,6 +58,7 @@
>
> extern const AVProfile ff_aac_profiles[];
> extern const AVProfile ff_dca_profiles[];
> +extern const AVProfile ff_eac3_profiles[];
> extern const AVProfile ff_dnxhd_profiles[];
> extern const AVProfile ff_h264_profiles[];
> extern const AVProfile ff_hevc_profiles[];
> --
> 2.25.1
>
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