On 4/2/18 9:36 AM, Jeyapal, Karthick wrote:
>
>
> On 3/23/18 10:57 AM, vdi...@akamai.com wrote:
>> From: Vishwanath Dixit <vdi...@akamai.com>
>>
>> availability time of Nth segment = availabilityStartTime + (N*segment
>> duration) - availabilityTimeOffset.
>> This field helps to reduce the latency by about a segment duration in
>> streaming mode.
>> ---
>> libavformat/dashenc.c | 11 ++++++++++-
>> 1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
>> index b62cb3e..d20bdba 100644
>> --- a/libavformat/dashenc.c
>> +++ b/libavformat/dashenc.c
>> @@ -85,6 +85,7 @@ typedef struct OutputStream {
>> char filename[1024];
>> char full_path[1024];
>> char temp_path[1024];
>> + int64_t chunk_duration;
> Remove this variable chunk_duration, and instead create a variable directly
> for availabilityTimeOffset.
Thanks for the review. I have submitted the revised patch
https://patchwork.ffmpeg.org/patch/8312/
>> } OutputStream;
>>
>> typedef struct DASHContext {
>> @@ -343,8 +344,12 @@ static void output_segment_list(OutputStream *os,
>> AVIOContext *out, AVFormatCont
>> if (c->use_template) {
>> int timescale = c->use_timeline ?
>> os->ctx->streams[0]->time_base.den : AV_TIME_BASE;
>> avio_printf(out, "\t\t\t\t<SegmentTemplate timescale=\"%d\" ",
>> timescale);
>> - if (!c->use_timeline)
>> + if (!c->use_timeline) {
>> avio_printf(out, "duration=\"%d\" ", c->seg_duration);
>> + if (c->streaming && os->chunk_duration)
>> + avio_printf(out, "availabilityTimeOffset=\"%.3f\" ",
>> + ((double) c->seg_duration - os->chunk_duration)
>> / AV_TIME_BASE);
>> + }
>> avio_printf(out, "initialization=\"%s\" media=\"%s\"
>> startNumber=\"%d\">\n", c->init_seg_name, c->media_seg_name, c->use_timeline
>> ? start_number : 1);
>> if (c->use_timeline) {
>> int64_t cur_time = 0;
>> @@ -1283,6 +1288,10 @@ static int dash_write_packet(AVFormatContext *s,
>> AVPacket *pkt)
>> format_date_now(c->availability_start_time,
>> sizeof(c->availability_start_time));
>>
>> + if (!os->chunk_duration && pkt->duration)
>> + os->chunk_duration = av_rescale_q(pkt->duration, st->time_base,
>> + AV_TIME_BASE_Q);
> Don’t use the term ‘chunk_duration’ here, as it is not clearly conceptualized
> in this file.
> Instead use the term ‘frame_duration’(local variable) to avoid confusion.
Thanks for the review. I have submitted the revised patch
https://patchwork.ffmpeg.org/patch/8312/
>> +
>> if (c->use_template && !c->use_timeline) {
>> elapsed_duration = pkt->pts - os->first_pts;
>> seg_end_duration = (int64_t) os->segment_index * c->seg_duration;
>
>
>
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