On 12/17/18, Michael Niedermayer <mich...@niedermayer.cc> wrote:
> On Mon, Dec 17, 2018 at 06:04:40PM +0100, Paul B Mahol wrote:
>> Hi,
>>
>> patches attached.
>
>> nut.h | 2 +
>> nutdec.c | 3 ++
>> nutenc.c | 87
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
>> 3 files changed, 88 insertions(+), 4 deletions(-)
>> 870df19d733f29294a2cb2e3ea5ed1a09745f3a4
>> 0001-avformat-nut-fix-duration-estimation-by-writing-EOR-.patch
>> From 80d6805fdf386182341fe72035ab88e06a602752 Mon Sep 17 00:00:00 2001
>> From: Paul B Mahol <one...@gmail.com>
>> Date: Mon, 17 Dec 2018 16:43:57 +0100
>> Subject: [PATCH 1/2] avformat/nut: fix duration estimation by writing EOR
>> packets
>>
>> Signed-off-by: Paul B Mahol <one...@gmail.com>
>> ---
>> libavformat/nut.h | 2 +
>> libavformat/nutdec.c | 3 ++
>> libavformat/nutenc.c | 87 ++++++++++++++++++++++++++++++++++++++++++--
>> 3 files changed, 88 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavformat/nut.h b/libavformat/nut.h
>> index a4409ee23d..d7ba86b5e5 100644
>> --- a/libavformat/nut.h
>> +++ b/libavformat/nut.h
>> @@ -76,6 +76,8 @@ typedef struct StreamContext {
>> int last_flags;
>> int skip_until_key_frame;
>> int64_t last_pts;
>> + int64_t last_dts;
>> + int64_t last_duration;
>> int time_base_id;
>> AVRational *time_base;
>> int msb_pts_shift;
>> diff --git a/libavformat/nutdec.c b/libavformat/nutdec.c
>> index 056ef59d00..f2490f9842 100644
>
>> --- a/libavformat/nutdec.c
>> +++ b/libavformat/nutdec.c
>> @@ -1080,6 +1080,9 @@ static int decode_frame(NUTContext *nut, AVPacket
>> *pkt, int frame_code)
>>
>> stc = &nut->stream[stream_id];
>>
>> + if (stc->last_flags & FLAG_EOR)
>> + return 1;
>
> EOR can occur in the middle of subtitle streams. It would be used to mark
> areas with no vissible subtitles.
> (The point behind this is that it allows seeking to consider a subtitle
> stream
> if and only if there are actually any displayed subtitles at that time)
>
> this code would break that
>
> also demxuer and muxer changes should be in seperate patches
>
>
>> +
>> if (stc->last_flags & FLAG_KEY)
>> stc->skip_until_key_frame = 0;
>>
>> diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c
>> index e9a3bb49db..c12b4cc8cf 100644
>> --- a/libavformat/nutenc.c
>> +++ b/libavformat/nutenc.c
>> @@ -940,6 +940,80 @@ fail:
>> return ret;
>> }
>>
>> +static void nut_update_max_pts(AVFormatContext *s, int stream_index,
>> int64_t pts)
>> +{
>> + NUTContext *nut = s->priv_data;
>> + StreamContext *nus = &nut->stream[stream_index];
>> +
>> + if (!nut->max_pts_tb || av_compare_ts(nut->max_pts, *nut->max_pts_tb,
>> pts, *nus->time_base) < 0) {
>> + nut->max_pts = pts;
>> + nut->max_pts_tb = nus->time_base;
>> + }
>> +}
>> +
>> +static int nut_write_eor(AVFormatContext *s, int stream_index)
>> +{
>> + AVIOContext *bc = s->pb, *dyn_bc;
>> + NUTContext *nut = s->priv_data;
>> + StreamContext *nus = &nut->stream[stream_index];
>> + int ret, frame_code, flags, needed_flags;
>> + int64_t pts = nus->last_pts + nus->last_duration;
>> + int64_t coded_pts;
>> + FrameCode *fc;
>> +
>> + coded_pts = pts & ((1 << nus->msb_pts_shift) - 1);
>> + if (ff_lsb2full(nus, coded_pts) != pts)
>> + coded_pts = pts + (1 << nus->msb_pts_shift);
>> +
>> + nut->last_syncpoint_pos = avio_tell(bc);
>> + ret = avio_open_dyn_buf(&dyn_bc);
>> + if (ret < 0)
>> + return ret;
>> + put_tt(nut, nus->time_base, dyn_bc, nus->last_dts +
>> nus->last_duration);
>> + ff_put_v(dyn_bc, 0);
>> +
>> + if (nut->flags & NUT_BROADCAST) {
>> + put_tt(nut, nus->time_base, dyn_bc,
>> + av_rescale_q(av_gettime(), AV_TIME_BASE_Q,
>> *nus->time_base));
>> + }
>> + put_packet(nut, bc, dyn_bc, 1, SYNCPOINT_STARTCODE);
>> +
>> + frame_code = -1;
>> + for (int i = 0; i < 256; i++) {
>> + FrameCode *fc = &nut->frame_code[i];
>> + int flags = fc->flags;
>> +
>> + if (flags & FLAG_INVALID)
>> + continue;
>> +
>> + if (!(flags & FLAG_CODED)) {
>> + continue;
>> + }
>> +
>> + frame_code = i;
>> + break;
>> + }
>> + av_assert0(frame_code != -1);
>> +
>> + fc = &nut->frame_code[frame_code];
>> + flags = fc->flags;
>> + needed_flags = FLAG_KEY | FLAG_EOR | FLAG_CODED_PTS |
>> FLAG_STREAM_ID;
>> +
>> + ffio_init_checksum(bc, ff_crc04C11DB7_update, 0);
>> + avio_w8(bc, frame_code);
>> + if (flags & FLAG_CODED) {
>> + ff_put_v(bc, (flags ^ needed_flags) & ~(FLAG_CODED));
>> + flags = needed_flags;
>> + }
>> + if (flags & FLAG_STREAM_ID) ff_put_v(bc, stream_index);
>> + if (flags & FLAG_CODED_PTS) ff_put_v(bc, coded_pts);
>> + ffio_get_checksum(bc);
>> +
>> + nut_update_max_pts(s, stream_index, nus->last_pts +
>> nus->last_duration);
>> +
>> + return 0;
>> +}
>> +
>> static int nut_write_packet(AVFormatContext *s, AVPacket *pkt)
>> {
>> NUTContext *nut = s->priv_data;
>> @@ -1136,6 +1210,8 @@ static int nut_write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>>
>> nus->last_flags = flags;
>> nus->last_pts = pkt->pts;
>> + nus->last_dts = pkt->dts;
>> + nus->last_duration = pkt->duration;
>>
>> //FIXME just store one per syncpoint
>> if (flags & FLAG_KEY && !(nut->flags & NUT_PIPE)) {
>> @@ -1150,10 +1226,7 @@ static int nut_write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>> nus->keyframe_pts[nut->sp_count] = pkt->pts;
>> }
>>
>> - if (!nut->max_pts_tb || av_compare_ts(nut->max_pts, *nut->max_pts_tb,
>> pkt->pts, *nus->time_base) < 0) {
>> - nut->max_pts = pkt->pts;
>> - nut->max_pts_tb = nus->time_base;
>> - }
>> + nut_update_max_pts(s, pkt->stream_index, pkt->pts);
>>
>> fail:
>> av_freep(&sm_buf);
>> @@ -1167,6 +1240,12 @@ static int nut_write_trailer(AVFormatContext *s)
>> AVIOContext *bc = s->pb, *dyn_bc;
>> int ret;
>>
>> + for (int i = 0; i < s->nb_streams; i++) {
>> + ret = nut_write_eor(s, i);
>> + if (ret < 0)
>> + return ret;
>> + }
>> +
>> while (nut->header_count < 3)
>> write_headers(s, bc);
>
> This violates the packet interleaving requirements
> if one stream ends. lets say at time 5sec and one continues with frames at
> 6,7,8 sec then the EOR frame for the stream ending at 5sec has to be
> written
> before the later frames.
How this violates it? It writes it at end. After end there is nothing.
>
> The best way to implement this will likely be with
> oformat->interleave_packet
> because at this level you know when the last packet is reached and you can
> also trivially inject an additional packet. That should then get
> interleaved
> automatically.
That function is no documented at all.
>
> also i suspect that index & syncpoint related code will need changes
> to support EORs
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