On Wed, Jun 25, 2025 at 5:55 PM Maryla Ustarroz-Calonge <maryla@google.com> wrote:

From: Maryla <maryla@google.com>

ITU-T T.35 provider codes are attributed by national bodies and it's possible to have collisions across countries. This is why the country code must always be checked as well.

Use if statements rather than nested switches which would be unreadable.

Rename some of the constants to match the corresponding organization. Add a constant for AOM. Write all constants with 4 hex digits to make it clear that they are 2-byte ids.

The code for V-Nova should be 0x5000 instead of 0x0050 according to the UK Register of Manufacturer Codes https://www.cix.co.uk/~bpechey/H221/h221code.htm but I have been unable to find any reference for what code should be used for LCEVC, and the author of the original change has not replied to my emails.

Signed-off-by: Maryla Ustarroz-Calonge <maryla@google.com> --- libavcodec/av1dec.c | 32 +++----- libavcodec/h2645_sei.c | 36 +++------ libavcodec/itut35.h | 21 ++++-- libavcodec/libdav1d.c | 154 +++++++++++++++++++------------------- libavformat/matroskadec.c | 2 +- libavformat/matroskaenc.c | 2 +- 6 files changed, 116 insertions(+), 131 deletions(-)

diff --git a/libavcodec/av1dec.c b/libavcodec/av1dec.c index 8ff1bf394c..be595484d1 100644 --- a/libavcodec/av1dec.c +++ b/libavcodec/av1dec.c @@ -965,13 +965,13 @@ static int export_itut_t35(AVCodecContext *avctx, AVFrame *frame, { GetByteContext gb; AV1DecContext *s = avctx->priv_data; - int ret, provider_code; + int ret, provider_code, country_code;

bytestream2_init(&gb, itut_t35->payload, itut_t35->payload_size);

provider_code = bytestream2_get_be16(&gb); - switch (provider_code) { - case ITU_T_T35_PROVIDER_CODE_ATSC: { + country_code = itut_t35->itu_t_t35_country_code ; + if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_ATSC) { uint32_t user_identifier = bytestream2_get_be32(&gb); switch (user_identifier) { case MKBETAG('G', 'A', '9', '4'): { // closed captions @@ -997,16 +997,13 @@ FF_ENABLE_DEPRECATION_WARNINGS default: // ignore unsupported identifiers break; } - break; - } - case ITU_T_T35_PROVIDER_CODE_SMTPE: { + } else if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_SAMSUNG) { AVDynamicHDRPlus *hdrplus; int provider_oriented_code = bytestream2_get_be16(&gb); int application_identifier = bytestream2_get_byte(&gb);

- if (itut_t35->itu_t_t35_country_code != ITU_T_T35_COUNTRY_CODE_US || - provider_oriented_code != 1 || application_identifier != 4) - break; + if (provider_oriented_code != 1 || application_identifier != 4) + return 0; // ignore

hdrplus = av_dynamic_hdr_plus_create_side_data(frame); if (!hdrplus) @@ -1016,28 +1013,23 @@ FF_ENABLE_DEPRECATION_WARNINGS bytestream2_get_bytes_left(&gb)); if (ret < 0) return ret; - break; - } - case ITU_T_T35_PROVIDER_CODE_DOLBY: { + } else if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_DOLBY) { int provider_oriented_code = bytestream2_get_be32(&gb); - if (itut_t35->itu_t_t35_country_code != ITU_T_T35_COUNTRY_CODE_US || - provider_oriented_code != 0x800) - break; + if (provider_oriented_code != 0x800) + return 0; // ignore

ret = ff_dovi_rpu_parse(&s->dovi, gb.buffer, gb.buffer_end - gb.buffer, avctx->err_recognition); if (ret < 0) { av_log(avctx, AV_LOG_WARNING, "Error parsing DOVI OBU.\n"); - break; // ignore + return 0; // ignore }

ret = ff_dovi_attach_side_data(&s->dovi, frame); if (ret < 0) return ret; - break; - } - default: // ignore unsupported provider codes - break; + } else { + // ignore unsupported provider codes }

return 0; diff --git a/libavcodec/h2645_sei.c b/libavcodec/h2645_sei.c index d17c4fb5f9..04432b6a8d 100644 --- a/libavcodec/h2645_sei.c +++ b/libavcodec/h2645_sei.c @@ -158,20 +158,10 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb, bytestream2_skipu(gb, 1); // itu_t_t35_country_code_extension_byte }

- if (country_code != ITU_T_T35_COUNTRY_CODE_US && - country_code != ITU_T_T35_COUNTRY_CODE_UK && - country_code != ITU_T_T35_COUNTRY_CODE_CN) { - av_log(logctx, AV_LOG_VERBOSE, - "Unsupported User Data Registered ITU-T T35 SEI message (country_code = %d)\n", - country_code); - return 0; - } - /* itu_t_t35_payload_byte follows */ provider_code = bytestream2_get_be16u(gb);

- switch (provider_code) { - case ITU_T_T35_PROVIDER_CODE_ATSC: { + if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_ATSC) { uint32_t user_identifier;

if (bytestream2_get_bytes_left(gb) < 4) @@ -189,9 +179,7 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb, user_identifier); break; } - break; - } - case ITU_T_T35_PROVIDER_CODE_LCEVC: { + } else if (country_code == ITU_T_T35_COUNTRY_CODE_UK && provider_code == ITU_T_T35_PROVIDER_CODE_VNOVA) { if (bytestream2_get_bytes_left(gb) < 2) return AVERROR_INVALIDDATA;

@@ -199,7 +187,7 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb, return decode_registered_user_data_lcevc(&h->lcevc, gb); } #if CONFIG_HEVC_SEI - case ITU_T_T35_PROVIDER_CODE_CUVA: { + else if (country_code == ITU_T_T35_COUNTRY_CODE_CN && provider_code == ITU_T_T35_PROVIDER_CODE_HDR_VIVID) { const uint16_t cuva_provider_oriented_code = 0x0005; uint16_t provider_oriented_code;

@@ -213,9 +201,7 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb, if (provider_oriented_code == cuva_provider_oriented_code) { return decode_registered_user_data_dynamic_hdr_vivid(&h->dynamic_hdr_vivid, gb); } - break; - } - case ITU_T_T35_PROVIDER_CODE_SMTPE: { + } else if(country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_SAMSUNG) { // A/341 Amendment - 2094-40 const uint16_t smpte2094_40_provider_oriented_code = 0x0001; const uint8_t smpte2094_40_application_identifier = 0x04; @@ -234,9 +220,7 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb, application_identifier == smpte2094_40_application_identifier) { return decode_registered_user_data_dynamic_hdr_plus(&h->dynamic_hdr_plus, gb); } - break; - } - case 0x5890: { // aom_provider_code + } else if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_AOM) { const uint16_t aom_grain_provider_oriented_code = 0x0001; uint16_t provider_oriented_code;

@@ -252,15 +236,13 @@ static int decode_registered_user_data(H2645SEI *h, GetByteContext *gb, gb->buffer, bytestream2_get_bytes_left(gb)); } - break; } - unsupported_provider_code: #endif - default: + else { + unsupported_provider_code: av_log(logctx, AV_LOG_VERBOSE, - "Unsupported User Data Registered ITU-T T35 SEI message (provider_code = %d)\n", - provider_code); - break; + "Unsupported User Data Registered ITU-T T35 SEI message (country_code = %d, provider_code = %d)\n", + country_code, provider_code); }

return 0; diff --git a/libavcodec/itut35.h b/libavcodec/itut35.h index a75ef37929..b8987d0b01 100644 --- a/libavcodec/itut35.h +++ b/libavcodec/itut35.h @@ -23,10 +23,21 @@ #define ITU_T_T35_COUNTRY_CODE_UK 0xB4 #define ITU_T_T35_COUNTRY_CODE_US 0xB5

-#define ITU_T_T35_PROVIDER_CODE_ATSC 0x31 -#define ITU_T_T35_PROVIDER_CODE_CUVA 0x04 -#define ITU_T_T35_PROVIDER_CODE_DOLBY 0x3B -#define ITU_T_T35_PROVIDER_CODE_LCEVC 0x50 -#define ITU_T_T35_PROVIDER_CODE_SMTPE 0x3C +// The Terminal Provider Code (or "Manufacturer Code") identifies the +// manufacturer within a country. An Assignment Authority appointed by the +// national body assigns this code nationally. The manufacturer code is always +// used in conjunction with a country code. +// - CN providers +#define ITU_T_T35_PROVIDER_CODE_HDR_VIVID 0x0004 +// - UK providers +// V-Nova should be 0x5000 according to UK Register of Manufacturer Codes +// https://www.cix.co.uk/~bpechey/H221/h221code.htm +// but FFmpeg has been using 0x0050 +#define ITU_T_T35_PROVIDER_CODE_VNOVA 0x0050 +// - US providers +#define ITU_T_T35_PROVIDER_CODE_ATSC 0x0031 +#define ITU_T_T35_PROVIDER_CODE_DOLBY 0x003B +#define ITU_T_T35_PROVIDER_CODE_AOM 0x5890 +#define ITU_T_T35_PROVIDER_CODE_SAMSUNG 0x003C

#endif /* AVCODEC_ITUT35_H */ diff --git a/libavcodec/libdav1d.c b/libavcodec/libdav1d.c index f4cbc927b5..a1158a23c4 100644 --- a/libavcodec/libdav1d.c +++ b/libavcodec/libdav1d.c @@ -386,6 +386,80 @@ static int libdav1d_receive_frame_internal(AVCodecContext *c, Dav1dPicture *p) return res; }

+static int parse_itut_t35_metadata(Libdav1dContext *dav1d, Dav1dPicture *p, + const Dav1dITUTT35 *itut_t35, AVCodecContext *c, + AVFrame *frame) { + GetByteContext gb; + int provider_code, country_code; + int res; + + bytestream2_init(&gb, itut_t35->payload, itut_t35->payload_size); + + provider_code = bytestream2_get_be16(&gb); + country_code = itut_t35->country_code; + if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_ATSC) { + uint32_t user_identifier = bytestream2_get_be32(&gb); + switch (user_identifier) { + case MKBETAG('G', 'A', '9', '4'): { // closed captions + AVBufferRef *buf = NULL; + + res = ff_parse_a53_cc(&buf, gb.buffer, bytestream2_get_bytes_left(&gb)); + if (res < 0) + return res; + if (!res) + return 0; // no cc found, ignore + + res = ff_frame_new_side_data_from_buf(c, frame, AV_FRAME_DATA_A53_CC, &buf); + if (res < 0) + return res; + +#if FF_API_CODEC_PROPS +FF_DISABLE_DEPRECATION_WARNINGS + c->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS; +FF_ENABLE_DEPRECATION_WARNINGS +#endif + break; + } + default: // ignore unsupported identifiers + break; + } + } else if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_SAMSUNG) { + AVDynamicHDRPlus *hdrplus; + int provider_oriented_code = bytestream2_get_be16(&gb); + int application_identifier = bytestream2_get_byte(&gb); + + if (provider_oriented_code != 1 || application_identifier != 4) + return 0; // ignore + + hdrplus = av_dynamic_hdr_plus_create_side_data(frame); + if (!hdrplus) + return AVERROR(ENOMEM); + + res = av_dynamic_hdr_plus_from_t35(hdrplus, gb.buffer, + bytestream2_get_bytes_left(&gb)); + if (res < 0) + return res; + } else if (country_code == ITU_T_T35_COUNTRY_CODE_US && provider_code == ITU_T_T35_PROVIDER_CODE_DOLBY) { + int provider_oriented_code = bytestream2_get_be32(&gb); + if (provider_oriented_code != 0x800) + return 0; // ignore + + res = ff_dovi_rpu_parse(&dav1d->dovi, gb.buffer, gb.buffer_end - gb.buffer, + c->err_recognition); + if (res < 0) { + av_log(c, AV_LOG_WARNING, "Error parsing DOVI OBU.\n"); + return 0; // ignore + } + + res = ff_dovi_attach_side_data(&dav1d->dovi, frame); + if (res < 0) + return res; + } else { + // ignore unsupported provider codes + } + return 0; +} + static int libdav1d_receive_frame(AVCodecContext *c, AVFrame *frame) { Libdav1dContext *dav1d = c->priv_data; @@ -514,83 +588,9 @@ static int libdav1d_receive_frame(AVCodecContext *c, AVFrame *frame) #else const Dav1dITUTT35 *itut_t35 = p->itut_t35; #endif - GetByteContext gb; - int provider_code; - - bytestream2_init(&gb, itut_t35->payload, itut_t35->payload_size); - - provider_code = bytestream2_get_be16(&gb); - switch (provider_code) { - case ITU_T_T35_PROVIDER_CODE_ATSC: { - uint32_t user_identifier = bytestream2_get_be32(&gb); - switch (user_identifier) { - case MKBETAG('G', 'A', '9', '4'): { // closed captions - AVBufferRef *buf = NULL; - - res = ff_parse_a53_cc(&buf, gb.buffer, bytestream2_get_bytes_left(&gb)); - if (res < 0) - goto fail; - if (!res) - break; - - res = ff_frame_new_side_data_from_buf(c, frame, AV_FRAME_DATA_A53_CC, &buf); - if (res < 0) - goto fail; - -#if FF_API_CODEC_PROPS -FF_DISABLE_DEPRECATION_WARNINGS - c->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS; -FF_ENABLE_DEPRECATION_WARNINGS -#endif - break; - } - default: // ignore unsupported identifiers - break; - } - break; - } - case ITU_T_T35_PROVIDER_CODE_SMTPE: { - AVDynamicHDRPlus *hdrplus; - int provider_oriented_code = bytestream2_get_be16(&gb); - int application_identifier = bytestream2_get_byte(&gb); - - if (itut_t35->country_code != ITU_T_T35_COUNTRY_CODE_US || - provider_oriented_code != 1 || application_identifier != 4) - break; - - hdrplus = av_dynamic_hdr_plus_create_side_data(frame); - if (!hdrplus) { - res = AVERROR(ENOMEM); - goto fail; - } - - res = av_dynamic_hdr_plus_from_t35(hdrplus, gb.buffer, - bytestream2_get_bytes_left(&gb)); - if (res < 0) - goto fail; - break; - } - case ITU_T_T35_PROVIDER_CODE_DOLBY: { - int provider_oriented_code = bytestream2_get_be32(&gb); - if (itut_t35->country_code != ITU_T_T35_COUNTRY_CODE_US || - provider_oriented_code != 0x800) - break; - - res = ff_dovi_rpu_parse(&dav1d->dovi, gb.buffer, gb.buffer_end - gb.buffer, - c->err_recognition); - if (res < 0) { - av_log(c, AV_LOG_WARNING, "Error parsing DOVI OBU.\n"); - break; // ignore - } - - res = ff_dovi_attach_side_data(&dav1d->dovi, frame); - if (res < 0) - goto fail; - break; - } - default: // ignore unsupported provider codes - break; - } + res = parse_itut_t35_metadata(dav1d, p, itut_t35, c, frame); + if (res < 0) + goto fail; #if FF_DAV1D_VERSION_AT_LEAST(6,9) } #endif diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index da5166319e..27baf3f18e 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -3931,7 +3931,7 @@ static int matroska_parse_block_additional(MatroskaDemuxContext *matroska, provider_code = bytestream2_get_be16u(&bc);

if (country_code != ITU_T_T35_COUNTRY_CODE_US || - provider_code != ITU_T_T35_PROVIDER_CODE_SMTPE) + provider_code != ITU_T_T35_PROVIDER_CODE_SAMSUNG) break; // ignore

provider_oriented_code = bytestream2_get_be16u(&bc); diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c index 408890fa89..8142d9125e 100644 --- a/libavformat/matroskaenc.c +++ b/libavformat/matroskaenc.c @@ -2869,7 +2869,7 @@ static int mkv_write_block(void *logctx, MatroskaMuxContext *mkv, size_t payload_size = sizeof(t35_buf) - 6;

bytestream_put_byte(&payload, ITU_T_T35_COUNTRY_CODE_US); - bytestream_put_be16(&payload, ITU_T_T35_PROVIDER_CODE_SMTPE); + bytestream_put_be16(&payload, ITU_T_T35_PROVIDER_CODE_SAMSUNG); bytestream_put_be16(&payload, 0x01); // provider_oriented_code bytestream_put_byte(&payload, 0x04); // application_identifier

-- 2.50.0.714.g196bf9f422-goog

Friendly ping. This is v2 where I changed from switch statements to if/else statements, which I think is easier to read and reduces nesting.