From a714150827c70f8baf2ec42dfecd9363c17e803d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= Date: Thu, 20 Sep 2012 10:40:10 +0200 Subject: [PATCH] lavf/movenc: add faststart option. --- Changelog | 1 + libavformat/movenc.c | 124 +++++++++++++++++++++++++++++++++++++++++-- libavformat/movenc.h | 3 +- 3 files changed, 122 insertions(+), 6 deletions(-) diff --git a/Changelog b/Changelog index b92c2e1d37..ce3c74b5cb 100644 --- a/Changelog +++ b/Changelog @@ -65,6 +65,7 @@ version next: - sendcmd and asendcmd filters - WebVTT demuxer and decoder (simple tags supported) - RTP packetization of JPEG +- faststart option in the MOV/MP4 muxer version 0.11: diff --git a/libavformat/movenc.c b/libavformat/movenc.c index a514b597c8..4b0a547e70 100644 --- a/libavformat/movenc.c +++ b/libavformat/movenc.c @@ -52,6 +52,7 @@ static const AVOption options[] = { { "separate_moof", "Write separate moof/mdat atoms for each track", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_SEPARATE_MOOF}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, { "frag_custom", "Flush fragments on caller requests", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FRAG_CUSTOM}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, { "isml", "Create a live smooth streaming feed (for pushing to a publishing point)", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_ISML}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, + { "faststart", "Run a second pass to put the moov at the beginning of the file", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_FASTSTART}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "movflags" }, FF_RTP_FLAG_OPTS(MOVMuxContext, rtp_flags), { "skip_iods", "Skip writing iods atom.", offsetof(MOVMuxContext, iods_skip), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM}, { "iods_audio_profile", "iods audio profile atom.", offsetof(MOVMuxContext, iods_audio_profile), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 255, AV_OPT_FLAG_ENCODING_PARAM}, @@ -3401,6 +3402,14 @@ static int mov_write_header(AVFormatContext *s) FF_MOV_FLAG_FRAG_CUSTOM)) mov->flags |= FF_MOV_FLAG_FRAGMENT; + /* faststart: moov at the beginning of the file, if supported */ + if (mov->flags & FF_MOV_FLAG_FASTSTART) { + if (mov->flags & FF_MOV_FLAG_FRAGMENT) + mov->flags &= ~FF_MOV_FLAG_FASTSTART; + else + mov->reserved_moov_size = -1; + } + /* Non-seekable output is ok if using fragmentation. If ism_lookahead * is enabled, we don't support non-seekable output at all. */ if (!s->pb->seekable && @@ -3573,7 +3582,8 @@ static int mov_write_header(AVFormatContext *s) if(mov->reserved_moov_size){ mov->reserved_moov_pos= avio_tell(pb); - avio_skip(pb, mov->reserved_moov_size); + if (mov->reserved_moov_size > 0) + avio_skip(pb, mov->reserved_moov_size); } if (!(mov->flags & FF_MOV_FLAG_FRAGMENT)) @@ -3633,6 +3643,100 @@ static int mov_write_header(AVFormatContext *s) return -1; } +/** + * This function gets the moov size if moved to the top of the file: the chunk + * offset table can switch between stco (32-bit entries) to co64 (64-bit + * entries) when the moov is moved to the top, so the size of the moov would + * change. It also updates the chunk offset tables. + */ +static int compute_moov_size(AVFormatContext *s) +{ + int i, moov_size, moov_size2; + MOVMuxContext *mov = s->priv_data; + + moov_size = get_moov_size(s); + if (moov_size < 0) + return moov_size; + + for (i = 0; i < mov->nb_streams; i++) + mov->tracks[i].data_offset += moov_size; + + moov_size2 = get_moov_size(s); + if (moov_size2 < 0) + return moov_size2; + + /* if the size changed, we just switched from stco to co64 and needs to + * update the offsets */ + if (moov_size2 != moov_size) + for (i = 0; i < mov->nb_streams; i++) + mov->tracks[i].data_offset += moov_size2 - moov_size; + + return moov_size2; +} + +static int shift_data(AVFormatContext *s) +{ + int ret = 0, moov_size; + MOVMuxContext *mov = s->priv_data; + int64_t pos, pos_end = avio_tell(s->pb); + uint8_t *buf, *read_buf[2]; + int read_buf_id = 0; + int read_size[2]; + AVIOContext *read_pb; + + moov_size = compute_moov_size(s); + if (moov_size < 0) + return moov_size; + + buf = av_malloc(moov_size * 2); + if (!buf) + return AVERROR(ENOMEM); + read_buf[0] = buf; + read_buf[1] = buf + moov_size; + + /* Shift the data: the AVIO context of the output can only be used for + * writing, so we re-open the same output, but for reading. It also avoids + * a read/seek/write/seek back and forth. */ + avio_flush(s->pb); + ret = avio_open(&read_pb, s->filename, AVIO_FLAG_READ); + if (ret < 0) { + av_log(s, AV_LOG_ERROR, "Unable to re-open %s output file for " + "the second pass (faststart)\n", s->filename); + goto end; + } + + /* mark the end of the shift to up to the last data we wrote, and get ready + * for writing */ + pos_end = avio_tell(s->pb); + avio_seek(s->pb, mov->reserved_moov_pos + moov_size, SEEK_SET); + + /* start reading at where the new moov will be placed */ + avio_seek(read_pb, mov->reserved_moov_pos, SEEK_SET); + pos = avio_tell(read_pb); + +#define READ_BLOCK do { \ + read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], moov_size); \ + read_buf_id ^= 1; \ +} while (0) + + /* shift data by chunk of at most moov_size */ + READ_BLOCK; + do { + int n; + READ_BLOCK; + n = read_size[read_buf_id]; + if (n <= 0) + break; + avio_write(s->pb, read_buf[read_buf_id], n); + pos += n; + } while (pos < pos_end); + avio_close(read_pb); + +end: + av_free(buf); + return ret; +} + static int mov_write_trailer(AVFormatContext *s) { MOVMuxContext *mov = s->priv_data; @@ -3670,11 +3774,19 @@ static int mov_write_trailer(AVFormatContext *s) ffio_wfourcc(pb, "mdat"); avio_wb64(pb, mov->mdat_size + 16); } - avio_seek(pb, mov->reserved_moov_size ? mov->reserved_moov_pos : moov_pos, SEEK_SET); + avio_seek(pb, mov->reserved_moov_size > 0 ? mov->reserved_moov_pos : moov_pos, SEEK_SET); - mov_write_moov_tag(pb, mov, s); - if(mov->reserved_moov_size){ - int64_t size= mov->reserved_moov_size - (avio_tell(pb) - mov->reserved_moov_pos); + if (mov->reserved_moov_size == -1) { + av_log(s, AV_LOG_INFO, "Starting second pass: moving header on top of the file\n"); + res = shift_data(s); + if (res == 0) { + avio_seek(s->pb, mov->reserved_moov_pos, SEEK_SET); + mov_write_moov_tag(pb, mov, s); + } + } else if (mov->reserved_moov_size > 0) { + int64_t size; + mov_write_moov_tag(pb, mov, s); + size = mov->reserved_moov_size - (avio_tell(pb) - mov->reserved_moov_pos); if(size < 8){ av_log(s, AV_LOG_ERROR, "reserved_moov_size is too small, needed %"PRId64" additional\n", 8-size); return -1; @@ -3684,6 +3796,8 @@ static int mov_write_trailer(AVFormatContext *s) for(i=0; i