[FFmpeg-user] Real-time HAP encoded streaming

[Kenneth Fields]

Hi,
in general documentation, 
Supported External Libraries, Formats, Codecs or Features 
=
I see Vidvox HAP under 2.1 file formats and not under video codecs. 
Can real-time HAP encoded network streaming be done? Anyone stats 
or reports on P2P HAP encoded streaming latency?

A normal, H.264 codec is unusable for p2p conferencing/performing as it
takes seconds to encode. I send audio separately (uncompressed
with Jacktrip), so the audio gets there first, without compression delay.

We want to use the GPU for HAP encoding.

On wikipedia:
https://en.wikipedia.org/wiki/List_of_codecs 

I see:
Realtime[edit 
]
Hap/Hap Alpha/Hap Q
VIDVOX hap codec
FFmpeg
DXV Codec
Resolume DXV Codec
FFmpeg (decoder only)

Thanks,
Ken
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Re: [FFmpeg-user] ProRes change framerate

[Carl Eugen Hoyos]

Fabrice Saudoyez  staytuned.be> writes:

> Any possibility without re-encoding ?

You can test the input option -r.

Please do not top-post here, Carl Eugen

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Re: [FFmpeg-user] Skipping on recording from PulseAudio

[Kieran Dunbar]

On 02/01/2016 22:24, Carl Eugen Hoyos wrote:

Kieran Dunbar  ffmpeg.org> writes:


I'm currently using ffmpeg to automatically record
audio from a sound card using PulseAudio. But
unfortunately the output files seem to skip
throughout

Is the issue also reproducible with the alsa
input device?

Carl Eugen

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Hi Carl,

That seems to have fixed the issue, thanks a lot!

Many Thanks,
Kieran
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[FFmpeg-user] Frames in a stream

[Nicholas Robbins]

I have been using the following to get a count of the frames in video:

PROBE=`/usr/bin/ffprobe -select_streams v -show_streams -count_frames -i 
${VIDEO} 2>&1`
FC=`/bin/echo "$PROBE" | /bin/grep nb_read_frames | /usr/bin/cut -d"=" -f2`

Recently I noticed that my regular ffmpeg/ffprobe invocations now have a more 
extensive metadata section, including, for instance:

...
Stream #0:0(eng): Video: mpeg2video (Main), yuv420p(tv), 720x480 [SAR 32:27 DAR 
16:9], max. 7500 kb/s, SAR 186:157 DAR 279:157, 29.97 fps, 29.97 tbr, 1k tbn, 
59.94 tbc
Metadata:
BPS-eng : 549782
DURATION-eng: 02:00:22.51530
NUMBER_OF_FRAMES-eng: 173168
...

For the sample I've tested, these two methods agree. 

My question is, where is the NUMBER_OF_FRAMES-eng obtained? Is it accurate?

For instance, note that this video is labeled as 29.97 fps, but quick 
arithmetic gives 23.976 fps as the actual frame rate. Transcoding with output 
option -r 24000/1001 produced no dropped frames.

Thanks,

Nick
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