diff --git a/libavcodec/ttmlenc.h b/libavcodec/ttmlenc.h index c1dd5ec990..c3bb11478d 100644 --- a/libavcodec/ttmlenc.h +++ b/libavcodec/ttmlenc.h @@ -25,4 +25,9 @@ #define TTMLENC_EXTRADATA_SIGNATURE "lavc-ttmlenc" #define TTMLENC_EXTRADATA_SIGNATURE_SIZE (sizeof(TTMLENC_EXTRADATA_SIGNATURE) - 1) +static const char ttml_default_namespacing[] = +" xmlns=\"http://www.w3.org/ns/ttml\"\n" +" xmlns:ttm=\"http://www.w3.org/ns/ttml#metadata\"\n" +" xmlns:tts=\"http://www.w3.org/ns/ttml#styling\"\n"; + #endif /* AVCODEC_TTMLENC_H */ diff --git a/libavformat/ttmlenc.c b/libavformat/ttmlenc.c index 940f8bbd4e..34a0107a14 100644 --- a/libavformat/ttmlenc.c +++ b/libavformat/ttmlenc.c @@ -37,6 +37,11 @@ enum TTMLPacketType { PACKET_TYPE_DOCUMENT, }; +struct TTMLHeaderParameters { + const char *tt_element_params; + const char *pre_body_elements; +}; + typedef struct TTMLMuxContext { enum TTMLPacketType input_type; unsigned int document_written; @@ -45,10 +50,9 @@ typedef struct TTMLMuxContext { static const char ttml_header_text[] = "\n" "\n" +"%s" " \n" "
\n"; @@ -72,6 +76,48 @@ static void ttml_write_time(AVIOContext *pb, const char tag[], tag, hour, min, sec, millisec); } +static int ttml_set_header_values_from_extradata( + AVCodecParameters *par, struct TTMLHeaderParameters *header_params) +{ + size_t additional_data_size = + par->extradata_size - TTMLENC_EXTRADATA_SIGNATURE_SIZE; + char *value = + (char *)par->extradata + TTMLENC_EXTRADATA_SIGNATURE_SIZE; + size_t value_size = av_strnlen(value, additional_data_size); + struct TTMLHeaderParameters local_params = { 0 }; + + if (!additional_data_size) { + // simple case, we don't have to go through local_params and just + // set default fall-back values (for old extradata format). + header_params->tt_element_params = ttml_default_namespacing; + header_params->pre_body_elements = ""; + + return 0; + } + + if (value_size == additional_data_size || + value[value_size] != '\0') + return AVERROR_INVALIDDATA; + + local_params.tt_element_params = value; + + additional_data_size -= value_size + 1; + value += value_size + 1; + if (!additional_data_size) + return AVERROR_INVALIDDATA; + + value_size = av_strnlen(value, additional_data_size); + if (value_size == additional_data_size || + value[value_size] != '\0') + return AVERROR_INVALIDDATA; + + local_params.pre_body_elements = value; + + *header_params = local_params; + + return 0; +} + static int ttml_write_header(AVFormatContext *ctx) { TTMLMuxContext *ttml_ctx = ctx->priv_data; @@ -103,8 +149,22 @@ static int ttml_write_header(AVFormatContext *ctx) avpriv_set_pts_info(st, 64, 1, 1000); - if (ttml_ctx->input_type == PACKET_TYPE_PARAGRAPH) - avio_printf(pb, ttml_header_text, printed_lang); + if (ttml_ctx->input_type == PACKET_TYPE_PARAGRAPH) { + struct TTMLHeaderParameters header_params; + int ret = ttml_set_header_values_from_extradata( + st->codecpar, &header_params); + if (ret < 0) { + av_log(ctx, AV_LOG_ERROR, + "Failed to parse TTML header values from extradata: " + "%s!\n", av_err2str(ret)); + return ret; + } + + avio_printf(pb, ttml_header_text, + header_params.tt_element_params, + printed_lang, + header_params.pre_body_elements); + } } return 0;