From 8ffcc826b3f34a954ba3f32171c7d7055f11379f Mon Sep 17 00:00:00 2001 From: Vignesh Venkatasubramanian Date: Wed, 8 May 2013 16:59:32 -0700 Subject: [PATCH] Adding support for muxing VP8 Alpha files This patch adds support for muxing VP8 Alpha Files. The Alpha channel data is placed in BlockAdditional element of the matroska container. More information & exact spec on how this is implemented can be found here: http://goo.gl/wCP1y Signed-off-by: Vignesh Venkatasubramanian Signed-off-by: Michael Niedermayer --- libavformat/matroskaenc.c | 59 ++++++++++++++++++++++++++++++++------- 1 file changed, 49 insertions(+), 10 deletions(-) diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c index 371b9d0bf2..6e5daf4e4a 100644 --- a/libavformat/matroskaenc.c +++ b/libavformat/matroskaenc.c @@ -662,6 +662,12 @@ static int mkv_write_tracks(AVFormatContext *s) put_ebml_uint(pb, MATROSKA_ID_VIDEOSTEREOMODE, st_mode); } + if ((tag = av_dict_get(st->metadata, "alpha_mode", NULL, 0)) || + (tag = av_dict_get( s->metadata, "alpha_mode", NULL, 0)) || + (codec->pix_fmt == AV_PIX_FMT_YUVA420P)) { + put_ebml_uint(pb, MATROSKA_ID_VIDEOALPHAMODE, 1); + } + if (st->sample_aspect_ratio.num) { int64_t d_width = av_rescale(codec->width, st->sample_aspect_ratio.num, st->sample_aspect_ratio.den); if (d_width > INT_MAX) { @@ -1136,9 +1142,10 @@ static void mkv_write_block(AVFormatContext *s, AVIOContext *pb, { MatroskaMuxContext *mkv = s->priv_data; AVCodecContext *codec = s->streams[pkt->stream_index]->codec; - uint8_t *data = NULL; - int offset = 0, size = pkt->size; + uint8_t *data = NULL, *side_data = NULL; + int offset = 0, size = pkt->size, side_data_size = 0; int64_t ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : pkt->pts; + uint64_t additional_id = 0; av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size %d, " "pts %" PRId64 ", dts %" PRId64 ", duration %d, flags %d\n", @@ -1156,14 +1163,46 @@ static void mkv_write_block(AVFormatContext *s, AVIOContext *pb, offset = 8; } - put_ebml_id(pb, blockid); - put_ebml_num(pb, size+4, 0); - avio_w8(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126 - avio_wb16(pb, ts - mkv->cluster_pts); - avio_w8(pb, flags); - avio_write(pb, data + offset, size); - if (data != pkt->data) - av_free(data); + side_data = av_packet_get_side_data(pkt, + AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL, + &side_data_size); + if (side_data) { + additional_id = AV_RB64(side_data); + side_data += 8; + side_data_size -= 8; + } + + if (side_data_size && additional_id == 1) { + ebml_master block_group, block_additions, block_more; + block_group = start_ebml_master(pb, MATROSKA_ID_BLOCKGROUP, 0); + put_ebml_id(pb, MATROSKA_ID_BLOCK); + put_ebml_num(pb, size+4, 0); + avio_w8(pb, 0x80 | (pkt->stream_index + 1)); // track number + avio_wb16(pb, ts - mkv->cluster_pts); + avio_w8(pb, flags); + avio_write(pb, data + offset, size); + if (data != pkt->data) + av_free(data); + block_additions = start_ebml_master(pb, MATROSKA_ID_BLOCKADDITIONS, 0); + block_more = start_ebml_master(pb, MATROSKA_ID_BLOCKMORE, 0); + put_ebml_uint(pb, MATROSKA_ID_BLOCKADDID, 1); + put_ebml_id(pb, MATROSKA_ID_BLOCKADDITIONAL); + put_ebml_num(pb, side_data_size, 0); + avio_write(pb, side_data, side_data_size); + end_ebml_master(pb, block_more); + end_ebml_master(pb, block_additions); + end_ebml_master(pb, block_group); + } + else { + put_ebml_id(pb, blockid); + put_ebml_num(pb, size+4, 0); + avio_w8(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126 + avio_wb16(pb, ts - mkv->cluster_pts); + avio_w8(pb, flags); + avio_write(pb, data + offset, size); + if (data != pkt->data) + av_free(data); + } } static int srt_get_duration(uint8_t **buf)