BtbN changed the topic of #ffmpeg to: Welcome to the FFmpeg USER support channel | Development channel: #ffmpeg-devel | Bug reports: https://ffmpeg.org/bugreports.html | Wiki: https://trac.ffmpeg.org/ | This channel is publically logged | FFmpeg 7.0 is released
peac has quit [Server closed connection]
peac has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
minimal has quit [Quit: Leaving]
phinxy has joined #ffmpeg
<phinxy> I have a h264+aac file with broken frames in it I'm guessing, it's from a VHS capture. Is a re-encoding going to fix anything broken in it? I noticed the audio would disappear a couple minutes in if the file was trimmed with -c:v copy and -c:a copy with only a -t to trim away the end.
iive has quit [Quit: They came for me...]
<phinxy> trimming with -c:v copy and -c:a aac seems to have worked better, why?
michaelni has joined #ffmpeg
lexano has quit [Ping timeout: 252 seconds]
michaelni has quit [Ping timeout: 252 seconds]
BSaboia has quit [Server closed connection]
BSaboia has joined #ffmpeg
s55 has quit [Server closed connection]
s55 has joined #ffmpeg
shubbar has quit [Quit: Leaving]
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
Polochon_street has quit [Server closed connection]
Polochon_street has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
michaelni has joined #ffmpeg
nrg has quit [Quit: ZNC - https://znc.in]
nrg has joined #ffmpeg
lucasta has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
Corroddity has quit [Quit: WeeChat 4.2.2]
Corroddity has joined #ffmpeg
monkeybusiness has quit [Server closed connection]
lemourin has quit [Quit: The Lounge - https://thelounge.chat]
lemourin has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
cockroach has quit [Quit: leaving]
FH_thecat has joined #ffmpeg
lucasta has quit [Remote host closed the connection]
xoip has quit [Server closed connection]
KombuchaKip has quit [Server closed connection]
Tinos has joined #ffmpeg
KombuchaKip has joined #ffmpeg
markizano has quit [Server closed connection]
markizano has joined #ffmpeg
turlando has quit [Ping timeout: 246 seconds]
flotwig has quit [Server closed connection]
flotwig has joined #ffmpeg
Apollyon has joined #ffmpeg
Some_Person has joined #ffmpeg
Apollyon has quit [Ping timeout: 272 seconds]
Nemo_pi has quit [Server closed connection]
emanuele6 has quit [Read error: Connection reset by peer]
turlando has joined #ffmpeg
l4yer has joined #ffmpeg
Sl4yer has quit [Ping timeout: 272 seconds]
emanuele6 has joined #ffmpeg
CounterPillow has quit [Server closed connection]
CounterPillow has joined #ffmpeg
archivist99 has joined #ffmpeg
GNU_world has quit [Ping timeout: 264 seconds]
MisterMinister has quit [Ping timeout: 248 seconds]
namazso has quit [Ping timeout: 245 seconds]
namazso has joined #ffmpeg
ePirat has quit [Server closed connection]
ePirat has joined #ffmpeg
relue has joined #ffmpeg
emanuele6 has quit [Read error: Connection reset by peer]
JEEB has quit [Server closed connection]
JEEB has joined #ffmpeg
emanuele6 has joined #ffmpeg
emanuele6 has quit [Read error: Connection reset by peer]
yans has quit [Remote host closed the connection]
HarshK23 has joined #ffmpeg
NaviTheFairy has quit [Server closed connection]
NaviTheFairy has joined #ffmpeg
troyt has quit [Server closed connection]
troyt has joined #ffmpeg
SystemError has quit [Ping timeout: 260 seconds]
emanuele6 has joined #ffmpeg
SystemError has joined #ffmpeg
rvalue- has joined #ffmpeg
rvalue has quit [Ping timeout: 264 seconds]
rvalue- is now known as rvalue
Dotz0cat_ has joined #ffmpeg
Dotz0cat has quit [Ping timeout: 245 seconds]
Dotz0cat_ is now known as Dotz0cat
Marth64 has joined #ffmpeg
nact has quit [Server closed connection]
nact has joined #ffmpeg
peterLustig67 has joined #ffmpeg
AbleBacon has quit [Read error: Connection reset by peer]
mrelcee has quit [Server closed connection]
JanC_ has joined #ffmpeg
JanC has quit [Killed (lead.libera.chat (Nickname regained by services))]
JanC_ is now known as JanC
mrelcee has joined #ffmpeg
koi has quit [Server closed connection]
koi has joined #ffmpeg
nitroxis has quit [Server closed connection]
nitroxis has joined #ffmpeg
lavaball has joined #ffmpeg
anticw has quit [Server closed connection]
anticw has joined #ffmpeg
SystemError has quit [Read error: Connection reset by peer]
beaver has quit [Remote host closed the connection]
cmc_ has quit [Read error: Connection reset by peer]
xx has joined #ffmpeg
cmc_ has joined #ffmpeg
beaver has joined #ffmpeg
utsweetyfish has quit [Server closed connection]
SystemError has joined #ffmpeg
Hackerpcs has quit [Ping timeout: 244 seconds]
ttys000 has quit [Server closed connection]
Hackerpcs has joined #ffmpeg
utsweetyfish has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
rv1sr has joined #ffmpeg
nitrix has quit [Server closed connection]
nitrix has joined #ffmpeg
ttys000 has joined #ffmpeg
relue has quit [Ping timeout: 248 seconds]
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
Vesryn has quit [Server closed connection]
Vesryn has joined #ffmpeg
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
memset has joined #ffmpeg
Hackerpcs has joined #ffmpeg
microchip_ has quit [Quit: There is no spoon!]
Hackerpcs has quit [Max SendQ exceeded]
microchip_ has joined #ffmpeg
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
lavaball has quit [Remote host closed the connection]
lavaball has joined #ffmpeg
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
Hackerpcs has joined #ffmpeg
emmanuelux has quit [Quit: au revoir]
Hackerpcs has quit [Max SendQ exceeded]
Hackerpcs has joined #ffmpeg
echelon has quit [Remote host closed the connection]
beaver has quit [Read error: Connection reset by peer]
xx has quit [Read error: Connection reset by peer]
memset has quit [Remote host closed the connection]
chiselfuse has quit [Remote host closed the connection]
Hackerpcs has quit [Max SendQ exceeded]
chiselfuse has joined #ffmpeg
xx has joined #ffmpeg
memset has joined #ffmpeg
echelon has joined #ffmpeg
beaver has joined #ffmpeg
Hackerpcs has joined #ffmpeg
Hackerpcs has quit [Max SendQ exceeded]
Hackerpcs has joined #ffmpeg
YuGiOhJCJ has joined #ffmpeg
Kobaz has quit [Server closed connection]
Kobaz has joined #ffmpeg
frojnd has quit [Server closed connection]
frojnd has joined #ffmpeg
upekkha has quit [Server closed connection]
upekkha has joined #ffmpeg
beaver has quit [Quit: newer kernel]
Mavrik has quit [Server closed connection]
Mavrik has joined #ffmpeg
beaver has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
rsx has joined #ffmpeg
treefrob has quit [Server closed connection]
treefrob has joined #ffmpeg
Unit640 has joined #ffmpeg
<Unit640> https://ffmpeg.org/ffmpeg.html <-- I cannot find a single mention of "-pred mixed" or "-pred" or "pred" anywhere...
<Unit640> Yesterday, I was told in here to "add -pred mixed if you want to use png".
<Unit640> Although I now see that `ffmpeg -h encoder=png` does output something about -pred and mixed...
<Unit640> "Prediction method (from 0 to 5) (default none)"
<Unit640> That's all it documents, though.
kuba-orlik0397 has quit [Remote host closed the connection]
<Unit640> I'm trying my script now with `-pred mixed` added to it, and it indeed seems to work MUCH better now! It makes the PNG files smaller instead of bigger/identical.
kuba-orlik0397 has joined #ffmpeg
<Unit640> Why is the default "prediction method" none, though?
<Unit640> furq: Perhaps I should address you since you were the one who helpefully mentioned that magical attribute.
deetwelve has quit [Server closed connection]
deetwelve has joined #ffmpeg
Rena has quit [Server closed connection]
Rena has joined #ffmpeg
farter has joined #ffmpeg
<farter> ahhh when i pass in YUVJ444P for h264_nvenc, it fails in encode_preinit_video "Specified pixel format yuvj444p is invalid or not supported" ... if we're going to split color_range from pix_fmt, it seems we should check as the tuple (pixfmt,colorrange) here, cuz i think it's correct to say an encoder is not guaranteed to support full_range even if it supports limited_range?
Corroddity has quit [Quit: WeeChat 4.3.4]
foul_owl has quit [Server closed connection]
foul_owl has joined #ffmpeg
<farter> ff_nvenc_pix_fmts contains no J, so
Corroddity has joined #ffmpeg
Corroddity has quit [Max SendQ exceeded]
Corroddity has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
farter has quit [Remote host closed the connection]
farter has joined #ffmpeg
zmt01 has joined #ffmpeg
zmt00 has quit [Ping timeout: 246 seconds]
lavaball has quit [Quit: lavaball]
lavaball has joined #ffmpeg
murb has quit [Server closed connection]
murb has joined #ffmpeg
kuba-orlik0397 has quit [Read error: Connection reset by peer]
kuba-orlik0397 has joined #ffmpeg
trillion_exabyte has quit [Ping timeout: 258 seconds]
pa has quit [Server closed connection]
trillion_exabyte has joined #ffmpeg
dbal has joined #ffmpeg
Tinos has quit [Ping timeout: 256 seconds]
FH_thecat has quit [Ping timeout: 248 seconds]
YuGiOhJCJ has quit [Remote host closed the connection]
kuba-orlik0397 has quit [Remote host closed the connection]
YuGiOhJCJ has joined #ffmpeg
kuba-orlik0397 has joined #ffmpeg
trillion_exabyte has quit [Ping timeout: 245 seconds]
brocellous has quit [Server closed connection]
brocellous has joined #ffmpeg
Peetz0r has quit [Server closed connection]
Peetz0r has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
five61848033 has quit [Remote host closed the connection]
five61848033 has joined #ffmpeg
trillion_exabyte has joined #ffmpeg
lexano has joined #ffmpeg
tsujp has quit [Server closed connection]
tsujp has joined #ffmpeg
sjs has quit [Server closed connection]
sjs has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
nrg has quit [Ping timeout: 244 seconds]
nrg has joined #ffmpeg
trillion_exabyte has quit [Ping timeout: 245 seconds]
trillion_exabyte has joined #ffmpeg
minimal has joined #ffmpeg
Brocker has quit [Server closed connection]
Brocker has joined #ffmpeg
trillion_exabyte has quit [Ping timeout: 256 seconds]
trillion_exabyte has joined #ffmpeg
farter has quit [Remote host closed the connection]
farter has joined #ffmpeg
SystemError has quit [Remote host closed the connection]
antto has quit [Server closed connection]
antto has joined #ffmpeg
SystemError has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
lucasta has joined #ffmpeg
sonicrules1234 has quit [Server closed connection]
sonicrules1234 has joined #ffmpeg
moxie has quit [Server closed connection]
moxie has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
FH_thecat has joined #ffmpeg
strudl has quit [Server closed connection]
strudl has joined #ffmpeg
lockywolf has quit [Server closed connection]
lockywolf has joined #ffmpeg
SystemError has quit [Remote host closed the connection]
Exa has quit [Server closed connection]
Exa has joined #ffmpeg
trillion_exabyte has quit [Ping timeout: 264 seconds]
luser1 has quit [Server closed connection]
luser1 has joined #ffmpeg
trillion_exabyte has joined #ffmpeg
SystemError has joined #ffmpeg
<realies> can adeclick be targeting only a specific time region of the audio? something like adeclick=between(t,10,20)?
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
peterLustig67 has quit [Remote host closed the connection]
peterLustig67 has joined #ffmpeg
<realies> i need to process a multi-hour long file and i know the specific places where a click would happen, wonder if i can optimise it somehow
jb3 has quit [Server closed connection]
jb3 has joined #ffmpeg
lusciouslover has quit [Read error: Connection reset by peer]
lusciouslover has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
luva8 has quit [Server closed connection]
luva8 has joined #ffmpeg
rsx has quit [Quit: rsx]
memset has quit [Remote host closed the connection]
memset has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
cworley_ has quit [Server closed connection]
cworley has joined #ffmpeg
MisterMinister has joined #ffmpeg
peterLustig67 has quit [Ping timeout: 256 seconds]
Tinos has joined #ffmpeg
HerbY_NL has joined #ffmpeg
HerbY_NL has quit [Client Quit]
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
kasper93_ has joined #ffmpeg
kasper93 has quit [Ping timeout: 264 seconds]
elvis_a_presley has quit [*.net *.split]
elvis_a_presley has joined #ffmpeg
kasper93_ is now known as kasper93
Tinos has quit [Remote host closed the connection]
Tinos has joined #ffmpeg
<another|> Unit640: maybe use a dedicated PNG optimizer like oxipng
j45 has quit [Server closed connection]
HerbY_NL has joined #ffmpeg
j45 has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
stonerl has quit [Quit: ZNC 1.9.0 - https://znc.in]
stonerl has joined #ffmpeg
HerbY_NL has quit [Quit: My MacBook has gone to sleep. ZZZzzz…]
troyt has quit [Ping timeout: 272 seconds]
troyt has joined #ffmpeg
acovrig601 has quit [Server closed connection]
acovrig601 has joined #ffmpeg
xoip has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
YuGiOhJCJ has quit [Quit: YuGiOhJCJ]
lucasta has quit [Quit: Leaving]
Tinos has quit [Remote host closed the connection]
Tinos has joined #ffmpeg
Brocker has quit [Read error: Connection reset by peer]
Brocker has joined #ffmpeg
tomaw has quit [Read error: Connection reset by peer]
kuba-orlik0397 has quit [Remote host closed the connection]
tomaw_ has joined #ffmpeg
kuba-orlik0397 has joined #ffmpeg
tomaw_ is now known as tomaw
beaver has quit [Remote host closed the connection]
AbleBacon has joined #ffmpeg
<Unit640> another|: Well, I asked about such things yesterday. I'll look into oxipng now.
<Unit640> But ffmpeg with the "magical parameter" seems to work quite well.
<Unit640> Bleh. No oxipng in Debian's apt...
Livio has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
Tinos has quit [Remote host closed the connection]
<CounterPillow> If you are using ancient boomerware like D*bian, you may wish to use optipng instead. oxipng is a rewrite of it without the security issues
yans has joined #ffmpeg
<CounterPillow> I can't check right now whether a newer Debian version has packaged oxipng because the garbage cgi perl crap Debian uses as its web package search just times out, presumably because Debian people are infinitely smart and do linear searches
trillion_exabyte has quit [Ping timeout: 246 seconds]
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
<znf> What's the proper subtitle container for dvd_sub?
trillion_exabyte has joined #ffmpeg
ossifrage has quit [Remote host closed the connection]
<znf> .VOB I guess?
<galad> define "proper"
coldfeet has joined #ffmpeg
coldfeet has quit [Remote host closed the connection]
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
<znf> galad, stand-alone sub, I'm trying to extract some dvd_sub streams to it's own separate container, but if I use file.sub, it the microDVD muxer complains
trillion_exabyte has quit [Ping timeout: 256 seconds]
trillion_exabyte has joined #ffmpeg
intrac has quit [Quit: Konversation terminated!]
intrac has joined #ffmpeg
georgereynolds8 has quit [Ping timeout: 252 seconds]
georgereynolds8 has joined #ffmpeg
<JanC> VOB files use (a subset of) an MPEG container, I think
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
<znf> .VOB seems to require an .IFO too
<znf> (in my subtitle edit)
<znf> guess I'm best at doing .mkv and then just parsing that
TheSilentLink has quit [Quit: Good Bye! My bouncer has probably crashed or lost connection to the internet...]
<Curid> never thought i'd see someone use the term boomerware on IRC
TheSilentLink has joined #ffmpeg
HerbY_NL has joined #ffmpeg
yawkat has quit [Ping timeout: 244 seconds]
HerbY_NL has quit [Quit: My MacBook has gone to sleep. ZZZzzz…]
Livio has quit [Ping timeout: 245 seconds]
Livio has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
farter has quit [Ping timeout: 256 seconds]
Livio has quit [Ping timeout: 258 seconds]
<kepstin> technically the subtitle images are complete in the vob, the issue is that the palette for them is located in the ifo file.
<kepstin> (in many cases, players have fallback or heuristic palettes to get you working subtitles if you open a bare vob)
Livio has joined #ffmpeg
Livio has quit [Client Quit]
memset has quit [Remote host closed the connection]
memset has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
rv1sr has quit []
beaver has joined #ffmpeg
j45 has quit [Quit: ZNC 1.8.2 - https://znc.in]
j45 has joined #ffmpeg
Haxxa has quit [Quit: Haxxa flies away.]
j45 has quit [Ping timeout: 246 seconds]
j45 has joined #ffmpeg
markizano has quit [Ping timeout: 252 seconds]
markizano has joined #ffmpeg
Haxxa has joined #ffmpeg
j45 has quit [Ping timeout: 248 seconds]
j45 has joined #ffmpeg
memset has quit [Remote host closed the connection]
memset has joined #ffmpeg
memset has quit [Remote host closed the connection]
memset has joined #ffmpeg
HarshK23 has quit [Quit: Connection closed for inactivity]
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
yans has quit [Quit: Let us play... Hide and Slay!]
lullerhaus has quit []
lullerhaus has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
emanuele6 has quit [Read error: Connection reset by peer]
emanuele6 has joined #ffmpeg
memset has quit [Remote host closed the connection]
memset has joined #ffmpeg
kizano has joined #ffmpeg
markizano has quit [Ping timeout: 260 seconds]
<Unit640> CounterPillow: "ancient boomerware"...
<Unit640> There's like less than a handful of actual Linux distros, Debian being one of them. All the others have some serious issue with the installer or about them, making it impossible to use them.
<sonicrules1234> That's the first time I've heard someone compare a linux distro's age to a human generation
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
<Unit640> Debian is the least garbagy Linux I've found, which probably says a lot about Linux. But trying to argue about that is futile.
<sonicrules1234> I think I've only ever used debian on a server. I use Arch as my daily driver
coldfeet has joined #ffmpeg
theobjectivedad has quit [Ping timeout: 260 seconds]
theobjectivedad has joined #ffmpeg
kuba-orlik0397 has quit [Read error: Connection reset by peer]
kuba-orlik0397 has joined #ffmpeg
<Unit640> Arch Linux is arch-userunfriendly.
<Unit640> Doesn't even have an installer unless you do some undocumented trick.
<Unit640> And what you get then is pathetic.
Unit640 has quit [Quit: Leaving]
five618480338 has joined #ffmpeg
<Marth64> znf: Use Matroska mks
<Marth64> It will properly store the timing and palette.
<Marth64> mkv is fine.
five61848033 has quit [Ping timeout: 265 seconds]
five618480338 is now known as five61848033
<znf> Marth64, oh, good point! I wanted to avoid "mkv" as Jellyfin would scan and add it as a video file...
<Marth64> Jellyfin may still pick up the mks if I recall correctly (it has been a while so not sure waht current behavior is). I just tuck the archived subs away in a subdirectory with .nomedia/.noignore in it
<Marth64> I do not keep graphical subs in active use for my personal library due to their ugliness.
<Marth64> But can't hurt to tr.
<Marth64> +y
<znf> I was actually doing it for the purpose of OCR-ing them
<znf> but meanwhile, I found SRTs that match the order of my files
<znf> so... :)
cmc_ has quit [Remote host closed the connection]
cmc_ has joined #ffmpeg
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
adema has quit [Server closed connection]
adema has joined #ffmpeg
LambdaComplex has quit [Server closed connection]
lavaball has quit [Quit: lavaball]
techietrash has quit [Server closed connection]
techietrash has joined #ffmpeg
SuicideShow has quit [Ping timeout: 248 seconds]
SuicideShow has joined #ffmpeg
coldfeet has quit [Remote host closed the connection]
kuba-orlik0397 has quit [Remote host closed the connection]
kuba-orlik0397 has joined #ffmpeg
KyleSiefring has quit [Server closed connection]
KyleSiefring has joined #ffmpeg
memset has quit [Ping timeout: 260 seconds]
memset has joined #ffmpeg
w1kl4s has quit [Server closed connection]
w1kl4s has joined #ffmpeg
energizer has quit [Server closed connection]
energizer has joined #ffmpeg
Warcop has quit [Remote host closed the connection]
kuba-orlik0397 has quit [Remote host closed the connection]
emmanuelux has joined #ffmpeg
kuba-orlik0397 has joined #ffmpeg
smashgrab has quit [Server closed connection]
sunyibo has quit [Server closed connection]
sunyibo has joined #ffmpeg
smashgrab has joined #ffmpeg
jess has joined #ffmpeg
mccobsta1 has joined #ffmpeg