Op donderdag 16-08-2012 om 04:49 uur [tijdzone +0100], schreef oliver
lynton:
> Hi Richard.
>
> I have been using Raffaella's excellent code at
> http://www.g-raffa.eu/Cinelerra/HOWTO/get_media_ready.html#_how_to_convert_your_hd_original_files_to_dnxhd
> which outputs AVID DNxHD video and RAW 16-bit PCM audio in a .mov
> container. High quality and ready for Cinelerra.
Hmm, I tried this, and indeed I get something out. Here's the command
line output from the ffmpeg (or actually avconv) command:
$ avconv -i my_file.mts -b 185M -s 1920x1080 -vcodec dnxhd -acodec
pcm_s16le my_file.mov
avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012
the Libav developers
built on Jun 12 2012 16:52:09 with gcc 4.6.3
Input #0, mpegts, from 'my_file.mts':
Duration: 00:00:19.27, start: 1.000033, bitrate: 16241 kb/s
Program 1
Stream #0.0[0x1011]: Video: h264 (High), yuv420p, 1920x1080 [PAR 1:1
DAR 16:9], 50 fps, 50 tbr, 90k tbn, 50 tbc
Stream #0.1[0x1100]: Audio: ac3, 48000 Hz, stereo, s16, 256 kb/s
Stream #0.2[0x1200]: Subtitle: pgssub
Incompatible pixel format 'yuv420p' for codec 'dnxhd', auto-selecting
format 'yuv422p'
[buffer @ 0x19173e0] w:1920 h:1080 pixfmt:yuv420p
[avsink @ 0x18fb460] auto-inserting filter 'auto-inserted scaler 0'
between the filter 'src' and the filter 'out'
[scale @ 0x18f8d60] w:1920 h:1080 fmt:yuv420p -> w:1920 h:1080
fmt:yuv422p flags:0x4
Output #0, mov, to 'my_file.mov':
Metadata:
encoder : Lavf53.21.0
Stream #0.0: Video: dnxhd, yuv422p, 1920x1080 [PAR 1:1 DAR 16:9],
q=2-31, 185000 kb/s, 50 tbn, 50 tbc
Stream #0.1: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (h264 -> dnxhd)
Stream #0:1 -> #0:1 (ac3 -> pcm_s16le)
Press ctrl-c to stop encoding
[... encoding information ...]
frame= 962 fps= 35 q=1.0 Lsize= 865571kB time=19.24
bitrate=368542.7kbits/s dup=481 drop=0
video:861952kB audio:3612kB global headers:0kB muxing overhead 0.000855%
(I get identical results when I use WinFF, except for a message that
ffmpeg is deprecated, so the CLI command is correct.)
BUT:
- The resulting .mov file is huge, as in: 22 times bigger than the
original .mts file. The original 19-second long clip my_file.mts is 38MB
in size, whereas my_file.mov is 846MB -- which boils down to a video
data rate of 44MBps. Am I correct in surmising that this later is fully
uncompressed HD?
- When I load the result (my_file.mov) in Cinelerra, something strange
happens: on the first track, I get the video data (my_file.mov #1),
below which I see a silent sound track (also named my_file.mov #1),
followed (on the same track) by another silent block named my_file.mov
#3, and below that is yet another silent sound track called my_file.mov
#2. Also see this screen shot:
http://www.linetec.nl/linux/cin_dnxhd.png
Why do I see this third audio track?
- When I try to play this in Cinelerra, things go badly wrong: playback
is choppy, there's no sound, and the whole thing screeches to a halt
just before the cursor reaches end of the part my_file.mov #3. At this
point, CPU load soars, and the computer becomes quite unresponsive.
- The .mov file won't play properly in any other player either (VLC,
KMplayer etc.).
So the question is: what am I doing wrong? Is the .mov file suitable for
rendering only, based on the editing list of a lower-quality proxy file
(I haven't actually tried this yet)? Or could it have to do with the
fact that the .mts file has 50 fps instead of 25 fps? Does it have
something to do with the 'Incompatible pixel format' mentioned in the
output? Or should I try building the latest Cinelerra-CV first and see
if that will handle the .mov file correctly?
Any insights are welcome!
Best regards,
Richard Rasker
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