AVI or AVC?

[agni451]

My original file is a .264 AVC file at ~20Mbps. I will be using MeGUI to reduce that to 10Mbps, but my question is, should I convert it to an XviD AVI at 10Mbps, or change it to an AVC at 10Mbps? Which would result in the highest quality for the bit rate, with all other things (resolution, no filters, etc) being the same? I should probably mention that I will be muxing the resulting video with the audio (encoded separately) with mkvmerge.


Also, on an unrelated note, how would I best go about extracting a portion (~1min clip) of an FLV file? I've got an FLV joiner, but no FLV splitter.

Sorry for the third question in a single thread, but could anyone give a brief explanation of what the different "Levels" mean for AVC video? I see most at L4.1, but what are "Levels," and how do they affect picture quality?

[Baldrick]

avc/h264.

[PuzZLeR]

My original file is a .264 AVC file at ~20Mbps. I will be using MeGUI to reduce that to 10Mbps, but my question is, should I convert it to an XviD AVI at 10Mbps, or change it to an AVC at 10Mbps? Which would result in the highest quality for the bit rate, with all other things (resolution, no filters, etc) being the same? I should probably mention that I will be muxing the resulting video with the audio (encoded separately) with mkvmerge.

Ceteris paribus, AVC has better compression than Xvid. At 10mbps, with HD, you should see this difference. But if you're using SD, at such a high bitrate this difference will be smaller.

However, Xvid has advantages such as less processing and better support among certified devices (you may need to verify whether it will support HD though if encoding to HD).

Xvid typically uses AVI, but can also, like AVC, be muxed into an MKV with what audio you choose.

But if you want to use the blu-ray spec that MeGUI offers, you may want to use AVC if playing on a blu-ray player.

Alot depends on what the playback device you wish to use and what it supports in your decision.

Also, on an unrelated note, how would I best go about extracting a portion (~1min clip) of an FLV file? I've got an FLV joiner, but no FLV splitter.

Did you try AviDemux?

Sorry for the third question in a single thread, but could anyone give a brief explanation of what the different "Levels" mean for AVC video? I see most at L4.1, but what are "Levels," and how do they affect picture quality?

Means generally nothing other than being a flag which indicates to the playback medium (if it cares) what's in the stream, such as max bitrate, max macroblocks, max resolution, max fps, etc. It has no effect on picture quality and can be inconsistent with what's really in the stream (in other words, you can try and lie by putting a different flag, but it depends...)

But nevertheless it's important among several playback devices which look for this flag. Level 4.1 is typically what's blu-ray compatible, among other devices such as game consoles. Mobiles may accept lower levels.

[agni451]

Ceteris paribus, AVC has better compression than Xvid. At 10mbps, with HD, you should see this difference. But if you're using SD, at such a high bitrate this difference will be smaller.

However, Xvid has advantages such as less processing and better support among certified devices (you may need to verify whether it will support HD though if encoding to HD).

Xvid typically uses AVI, but can also, like AVC, be muxed into an MKV with what audio you choose.

But if you want to use the blu-ray spec that MeGUI offers, you may want to use AVC if playing on a blu-ray player.

Alot depends on what the playback device you wish to use and what it supports in your decision.

Okay, I'll be going with AVC. Had to up the motion estimation because there's a lot of fast action, so this encode is going to be SLOW.

Luckily, I won't be playing this on a blu-ray player, just my computer, so I guess I don't have to worry too much about compatibility. Thanks for the heads up, though.

Did you try AviDemux?

AviDemux seems to freeze when I open an FLV (I have the latest version). I ended up just using ffmpeg command line directly and I did what I needed. Thanks.

[jagabo]

AVC Levels:
http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Levels

[yoda313]

@agni451 - will mp4 files with h264 work for you? If so here's what you can do:

Use winff to transcode the ORIGINAL flv to mp4. These have worked perfectly on my first generation wdtv media player. The first gen wdtv doesn't read the original flv files even though they are h264 but it reads the remuxed mp4 files perfectly. Mine happen to be 4:3 sd but I'm sure it works with hd widescreen ones.

Use this line in the additional parameters tab:

-vcodec copy -acodec copy

Thanks to bat999 for this information.

I'm pretty sure they worked ok on my ps3 too after muxing to mp4 - fyi there is no processing involved - the headers and file extension are changed without altering the video. Select mp4 in the convert to slot and select mp4 widescreen if they are widescreen video.

Mp4 should be pretty prevelant on many devices especially since they are originally h264 - just check your device to be sure.

[agni451]

Use this line in the additional parameters tab:

-vcodec copy -acodec copy

My final ffmpeg command line was

ffmpeg.exe -i video_in.flv -ss 00:01:00 -t 00:01:00 -vcodec copy -acodec copy video_out.flv

It worked perfectly.


About the AVC video- it took 12 hours on my i7 950 to encode, but the video was great- quality looked as good as the original at more than twice the bitrate. I just have a quick question- when I was playing it in VLC media player, at two distinct scenes pixels start dragging across the screen for about a second or two and the scene is completely unwatchable. However, when I view the same scenes in MPC-HC, it works just fine. Anyone else had this issue with VLC?