Error in Mp3 to Dv conversion

[rajivrp]

Hi,

I am trying to convert an mp3 into dv format using ffmpeg, but getting this error -

ffmpeg.exe -i C:\WebM\Audio_MP3.mp3 C:\WebM\Output.dv

ffmpeg version N-35462-g61b1d85, Copyright (c) 2000-2011 the FFmpeg developers
built on Dec 5 2011 14:22:27 with gcc 4.6.2
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libope
ncore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --en
able-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger -
-enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwben
c --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-
libxvid --enable-zlib
libavutil 51. 30. 0 / 51. 30. 0
libavcodec 53. 40. 0 / 53. 40. 0
libavformat 53. 24. 0 / 53. 24. 0
libavdevice 53. 4. 0 / 53. 4. 0
libavfilter 2. 51. 0 / 2. 51. 0
libswscale 2. 1. 0 / 2. 1. 0
libpostproc 51. 2. 0 / 51. 2. 0
[mp3 @ 00358660] max_analyze_duration 5000000 reached at 5015510
[mp3 @ 00358660] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'C:\WebM\Audio_MP3.mp3':
Metadata:
title : Zippit speech
artist : Unknown
genre : Blues
Duration: 00:00:41.43, start: 0.000000, bitrate: 127 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
[dv @ 01B435C0] Can't initialize DV format!
Make sure that you supply exactly two streams:
video: 25fps or 29.97fps, audio: 2ch/48kHz/PCM
(50Mbps allows an optional second audio stream)
Output #0, dv, to 'C:\WebM\Output.dv':
Metadata:
title : Zippit speech
artist : Unknown
genre : Blues
encoder : Lavf53.24.0
Stream #0:0: Audio: pcm_s16le, 44100 Hz, stereo, s16, 1411 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (mp3 -> pcm_s16le)
Could not write header for output file #0 (incorrect codec parameters ?)

Thanks,
Rajiv

[rajivrp]

Tried to give format and type explicitly, but same error -

ffmpeg.exe -i C:\WebM\Audio_MP3.mp3 -f dv -target ntsc-dv C:\WebM\Output.dv

ffmpeg version N-35462-g61b1d85, Copyright (c) 2000-2011 the FFmpeg developers
built on Dec 5 2011 14:22:27 with gcc 4.6.2
configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libope
ncore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --en
able-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger -
-enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwben
c --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-
libxvid --enable-zlib
libavutil 51. 30. 0 / 51. 30. 0
libavcodec 53. 40. 0 / 53. 40. 0
libavformat 53. 24. 0 / 53. 24. 0
libavdevice 53. 4. 0 / 53. 4. 0
libavfilter 2. 51. 0 / 2. 51. 0
libswscale 2. 1. 0 / 2. 1. 0
libpostproc 51. 2. 0 / 51. 2. 0
[mp3 @ 02458740] max_analyze_duration 5000000 reached at 5015510
[mp3 @ 02458740] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'C:\WebM\Audio_MP3.mp3':
Metadata:
title : Zippit speech
artist : Unknown
genre : Blues
Duration: 00:00:41.43, start: 0.000000, bitrate: 127 kb/s
Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16, 128 kb/s
File 'C:\WebM\Output.dv' already exists. Overwrite ? [y/N] y
Can't initialize DV format!
Make sure that you supply exactly two streams:
video: 25fps or 29.97fps, audio: 2ch/48kHz/PCM
(50Mbps allows an optional second audio stream)
Output #0, dv, to 'C:\WebM\Output.dv':
Metadata:
title : Zippit speech
artist : Unknown
genre : Blues
encoder : Lavf53.24.0
Stream #0:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (mp3 -> pcm_s16le)
Could not write header for output file #0 (incorrect codec parameters ?)

Can someone pls give any pointer ... not clear what exactly is wrong here.

Thanks.

[Case]

DV should have a video stream and an audio stream. You can't convert MP3 (audio only) to DV, as the source lacks video.
If you are trying to convert your MP3 file to something a DV video editor can use, then convert to PCM (wav).

[Cornucopia]

Doesn't matter if you "FORCE" it or not, you have no video as a source, so you can't make a video file as an output. If you have to, give it a simple, boilerplate video source (black screen or something).

Scott

(edit: Case, you beat me to the punch)

[rajivrp]

But then why am I successfully able to convert this mp3 into wmv, mov, mp4 etc .... are they all not video output formats as well (and so should need video part in source) ?? ........ What is so unique about DV, does it not have capability of carrying only Audio ?

[Cornucopia]

Because WMV, MOV, MP4, AVI, etc are MULTIPLEXED streams (Audio and/or Video, etc) inside a Multi-media CONTAINER format, whereas DV is a special type of ELEMENTARY VIDEO (multiplexed with audio) STREAM (no container). Even if the habit is for there to be video in them, mm Containers can usually exist with audio only as well.

All *.DV streams EXPECT there to be video. That's why it's called Digital Video.

Scott

[rajivrp]

Thanks very much ..

One last follow-up doubt .. would it hold true for MXF and GXF formats also ?? I am unable to convert this MP3 into those formats as well ..

By the way can anyone suggest any good documentation on audio-video fundamentals ? I am a new bee in this world and looking for one such guide ..

[Cornucopia]

Not sure about ffmpeg's compatibility with & support for MXF/GXF. But those containers are more like playlists (or more accurately - EDLs), maybe they also expect video elementary streams as input. Then you would have the same problem you do with your DV conversion.

Face it - while there does exist "silent video", for the great majority of time-based multi-media files, you either have AUDIO-ONLY or VIDEO-with-AUDIO. You are starting from an mp3 (AUDIO-ONLY type) and going to a VIDEO-with-AUDIO type. Where's the video going to come from? It doesn't appear in mid-air; you have to create it (separately) and add it as a source.

Scott

[rajivrp]

Got it ..... thanks a lot for the explanation !!