[FFmpeg-devel] [PATCH] avformat/flvdec: enhance parsing timestamps

Wed May 12 22:05:43 EEST 2021

On 5/12/2021 4:04 PM, James Almer wrote:
> On 5/12/2021 3:55 PM, Marton Balint wrote:
>> Take into account timezone. Use millisecond precision. Maybe we could 
>> also use
>> nanosecond, but there were some float rounding concerns.
> 
> Alexander Strasser wrote an alternative approach to using timezone in 
> https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2021-May/280179.html 
> yesterday.
> 
> And regarding the rounding concerns, we could maybe check for the 
> bitexact flag in avctx->flags and use it to either print 
> milli/nanoseconds or leave it as seconds.

Nevermind this part, this is lavf not lavc, and AVFormatContext bitexact 
flag is not meant for demuxers, only muxers.

> 
>>
>> Signed-off-by: Marton Balint <cus at passwd.hu>
>> ---
>>   libavformat/flvdec.c     | 13 ++-----------
>>   tests/ref/fate/flv-demux |  2 +-
>>   2 files changed, 3 insertions(+), 12 deletions(-)
>>
>> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
>> index ddaceaafe4..3791687072 100644
>> --- a/libavformat/flvdec.c
>> +++ b/libavformat/flvdec.c
>> @@ -28,6 +28,7 @@
>>   #include "libavutil/channel_layout.h"
>>   #include "libavutil/dict.h"
>>   #include "libavutil/opt.h"
>> +#include "libavutil/internal.h"
>>   #include "libavutil/intfloat.h"
>>   #include "libavutil/mathematics.h"
>>   #include "libavutil/time_internal.h"
>> @@ -682,17 +683,7 @@ static int amf_parse_object(AVFormatContext *s, 
>> AVStream *astream,
>>           } else if (amf_type == AMF_DATA_TYPE_STRING) {
>>               av_dict_set(&s->metadata, key, str_val, 0);
>>           } else if (amf_type == AMF_DATA_TYPE_DATE) {
>> -            time_t time;
>> -            struct tm t;
>> -            char datestr[128];
>> -            time =  date.milliseconds / 1000; // to seconds
>> -            gmtime_r(&time, &t);
>> -
>> -            // timezone is ignored, since there is no easy way to 
>> offset the UTC
>> -            // timestamp into the specified timezone
>> -            strftime(datestr, sizeof(datestr), "%Y-%m-%dT%H:%M:%SZ", 
>> &t);
>> -
>> -            av_dict_set(&s->metadata, key, datestr, 0);
>> +            avpriv_dict_set_timestamp(&s->metadata, key, 
>> -date.timezone * 60000000LL + 1000 * (int64_t)date.milliseconds);
>>           }
>>       }
>> diff --git a/tests/ref/fate/flv-demux b/tests/ref/fate/flv-demux
>> index 827b56ea09..3eede6eb00 100644
>> --- a/tests/ref/fate/flv-demux
>> +++ b/tests/ref/fate/flv-demux
>> @@ -605,4 +605,4 @@ 
>> packet|codec_type=audio|stream_index=1|pts=11656|pts_time=11.656000|dts=11656|dt 
>>
>>   
>> packet|codec_type=video|stream_index=0|pts=11678|pts_time=11.678000|dts=11678|dts_time=11.678000|duration=33|duration_time=0.033000|size=1190|pos=510794|flags=__|data_hash=CRC32:a0206c90 
>>
>>   
>> stream|index=0|codec_name=h264|profile=77|codec_type=video|codec_tag_string=[0][0][0][0]|codec_tag=0x0000|width=426|height=240|coded_width=426|coded_height=240|closed_captions=0|has_b_frames=1|sample_aspect_ratio=1:1|display_aspect_ratio=71:40|pix_fmt=yuv420p|level=21|color_range=unknown|color_space=unknown|color_transfer=unknown|color_primaries=unknown|chroma_location=left|field_order=progressive|refs=1|is_avc=true|nal_length_size=4|id=N/A|r_frame_rate=30000/1001|avg_frame_rate=30/1|time_base=1/1000|start_pts=0|start_time=0.000000|duration_ts=N/A|duration=N/A|bit_rate=393929|max_bit_rate=N/A|bits_per_raw_sample=8|nb_frames=N/A|nb_read_frames=N/A|nb_read_packets=351|extradata_hash=CRC32:07b85ca9|disposition:default=0|disposition:dub=0|disposition:original=0|disposition:comment=0|disposition:lyrics=0|disposition:karaoke=0|disposition:forced=0|disposition:hearing_impaired=0|disposition:visual_impaired=0|disposition:clean_effects=0|disposition:attached_pic=0|disposition:timed_thumbnail 
>>
>>   
>> s=0|disposition:captions=0|disposition:descriptions=0|disposition:metadata=0|disposition:dependent=0|disposition:still_image=0 
>>
>>   
>> stream|index=1|codec_name=aac|profile=1|codec_type=audio|codec_tag_string=[0][0][0][0]|codec_tag=0x0000|sample_fmt=fltp|sample_rate=22050|channels=2|channel_layout=stereo|bits_per_sample=0|id=N/A|r_frame_rate=0/0|avg_frame_rate=0/0|time_base=1/1000|start_pts=0|start_time=0.000000|duration_ts=N/A|duration=N/A|bit_rate=67874|max_bit_rate=N/A|bits_per_raw_sample=N/A|nb_frames=N/A|nb_read_frames=N/A|nb_read_packets=252|extradata_hash=CRC32:d039c029|disposition:default=0|disposition:dub=0|disposition:original=0|disposition:comment=0|disposition:lyrics=0|disposition:karaoke=0|disposition:forced=0|disposition:hearing_impaired=0|disposition:visual_impaired=0|disposition:clean_effects=0|disposition:attached_pic=0|disposition:timed_thumbnails=0|disposition:captions=0|disposition:descriptions=0|disposition:metadata=0|disposition:dependent=0|disposition:still_image=0 
>>
>> -format|filename=Enigma_Principles_of_Lust-part.flv|nb_streams=2|nb_programs=0|format_name=flv|start_time=0.000000|duration=210.209999|size=512000|bit_rate=19485|probe_score=100|tag:hasKeyframes=true|tag:hasMetadata=true|tag:datasize=11970544|tag:hasVideo=true|tag:canSeekToEnd=false|tag:lasttimestamp=210|tag:lastkeyframetimestamp=210|tag:audiosize=1791332|tag:hasAudio=true|tag:audiodelay=0|tag:videosize=10176110|tag:metadatadate=2011-02-27T11:00:33Z|tag:metadatacreator=inlet 
>> media FLVTool2 v1.0.6 - 
>> http://www.inlet-media.de/flvtool2|tag:hasCuePoints=false
>> +format|filename=Enigma_Principles_of_Lust-part.flv|nb_streams=2|nb_programs=0|format_name=flv|start_time=0.000000|duration=210.209999|size=512000|bit_rate=19485|probe_score=100|tag:hasKeyframes=true|tag:hasMetadata=true|tag:datasize=11970544|tag:hasVideo=true|tag:canSeekToEnd=false|tag:lasttimestamp=210|tag:lastkeyframetimestamp=210|tag:audiosize=1791332|tag:hasAudio=true|tag:audiodelay=0|tag:videosize=10176110|tag:metadatadate=2011-02-27T17:00:33.125000Z|tag:metadatacreator=inlet 
>> media FLVTool2 v1.0.6 - 
>> http://www.inlet-media.de/flvtool2|tag:hasCuePoints=false
>>
> 