Batch Remux AVCHD Files

[wwaag]

Is there a tool to batch remux a bunch (over 1000) of AVCHD (m2ts) clips? I simply want to replace the audio stream for each clip. The original AVCHD clips (from a Sony handycam) and the new audio clips (AC3) have the same file name. TSMuxer will do the remux, but one at a time would be impractical. Thanks.

wwaag

[poisondeathray]

You can do it with ffmpeg batch processing.

This example will copy the video, copy the new ac3 track, and create a new .mts with the name "new" appended to it. The original files won't be overwritten. You can change the directories if you want by specifying a path

e.g from commandline

for %a in ("*.mts") do ffmpeg -i "%~na.mts" -i "%~na.ac3" -c copy -map 0:0 -map 1:0 "%~na.new.mts"

or batch file, just replace the "%" with "%%"

for %%a in ("*.mts") do ffmpeg -i "%%~na.mts" -i "%%~na.ac3" -c copy -map 0:0 -map 1:0 "%%~na.new.mts"
pause

[poisondeathray]

I should mention this method doesn't keep the original file metadata (e.g. some cameras have GPS, date, time etc.. )

So for that and other reasons - you should always backup your original camera files in their own original folder structure if they are even remotely semi-important. (The original folder structure is necessary for NLE's to do seamless gaps between filespanned clips)

[wwaag]

Thanks for the quick reply. Have not used Ffmpeg before nor am I familiar with using command lines, so please bear with me. I downloaded and installed the latest 64bit version. Using the command line you provided, I changed the MTS to m2ts and the ac3 to wav (I haven't yet converted all my wav files to ac3). In a test directory, it did successfully execute and create new files with the .new extension. However, the new files had only the video stream--no audio. Mediainfo shows only a video track. Any ideas? Thanks.

wwaag

[poisondeathray]

Thanks for the quick reply. Have not used Ffmpeg before nor am I familiar with using command lines, so please bear with me. I downloaded and installed the latest 64bit version. Using the command line you provided, I changed the MTS to m2ts and the ac3 to wav (I haven't yet converted all my wav files to ac3). In a test directory, it did successfully execute and create new files with the .new extension. However, the new files had only the video stream--no audio. Mediainfo shows only a video track. Any ideas? Thanks.

yep - ffmpeg has problems muxing uncompressed pcm wav into transport streams . That's probably why

So batch encode the wav files to ac3 first, and use the original commandline, but with m2ts instead of mts (if your files are m2ts)

[poisondeathray]

Here is an example for batch encoding wav => AC3 . The bitrate is 384k, you can change that value if you want. The filename.ac3 will be derived from filename.wav (no "new" appended to the name) - hopefully filename.wav matches with the corresponding filename.m2ts that it's supposed to match up with, that way filename.ac3 will match

for %a in ("*.wav") do ffmpeg -i "%a" -acodec ac3 -b:a 384k "%~na.ac3"

[wwaag]

It works. Converted my wav files to ac3 and tried again. Thanks so much. Just curious--the new files are larger than the original (e.g. 215mb vs 226mb). The ac3 file was only 2mb. Is this normal?

wwaag

[poisondeathray]

It works. Converted my wav files to ac3 and tried again. Thanks so much. Just curious--the new files are larger than the original (e.g. 215mb vs 226mb). The ac3 file was only 2mb. Is this normal?

wwaag

It might be; what was the bitrate of the audio before and after?

Use mediainfo (view=>text) on the original file, and the "audio-replaced" file , copy & paste the text back here please

There are slightly different types of transport streams. For example, .m2ts have extra bytes as TC data, and others are sometimes padded

[wwaag]

Here are the two media info panes. I also notice there is a 17 msec delay in the new file. Can this be changed?

Original File--------------------------------------

General
ID : 0 (0x0)
Complete name : F:\Oregon 2013 March\Video Clips\Temp\20130328120742.m2ts
Format : BDAV
Format/Info : Blu-ray Video
File size : 210 MiB
Duration : 1mn 6s
Overall bit rate mode : Variable
Overall bit rate : 26.5 Mbps
Maximum Overall bit rate : 28.0 Mbps

Video
ID : 4113 (0x1011)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=1, N=15
Codec ID : 27
Duration : 1mn 6s
Bit rate mode : Variable
Bit rate : 25.2 Mbps
Maximum bit rate : 26.0 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 59.940 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.203
Stream size : 200 MiB (95%)

Audio
ID : 4352 (0x1100)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Codec ID : 129
Duration : 1mn 6s
Bit rate mode : Constant
Bit rate : 256 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Stream size : 2.03 MiB (1%)

Text
ID : 4608 (0x1200)
Menu ID : 1 (0x1)
Format : PGS
Codec ID : 144
Duration : 1mn 6s

New File------------------------------------------

General
ID : 1 (0x1)
Complete name : F:\Oregon 2013 March\Video Clips\Temp\20130328120742.new.m2ts
Format : BDAV
Format/Info : Blu-ray Video
File size : 221 MiB
Duration : 1mn 6s
Overall bit rate mode : Variable
Overall bit rate : 27.8 Mbps

Video
ID : 256 (0x100)
Menu ID : 1 (0x1)
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Format settings, GOP : M=1, N=15
Codec ID : 27
Duration : 1mn 6s
Bit rate mode : Variable
Bit rate : 26.0 Mbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 59.940 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.209
Stream size : 210 MiB (95%)

Audio
ID : 257 (0x101)
Menu ID : 1 (0x1)
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Codec ID : 129
Duration : 1mn 6s
Bit rate mode : Constant
Bit rate : 256 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Compression mode : Lossy
Delay relative to video : -17ms
Stream size : 2.03 MiB (1%)

Menu
ID : 4096 (0x1000)
Menu ID : 1 (0x1)
Duration : 1mn 6s
List : 256 (0x100) (AVC) / 257 (0x101) (AC-3)
Service name : Service01
Service provider : FFmpeg
Service type : digital television

[poisondeathray]

The filesize can change depending on the -muxrate you set . It's basically padding the transport stream. It's tricky business, and you can end up with buffer underflows or overflows if you're not careful. It's automatically set so I wouldn't touch it in ffmpeg. If you demux both those files (e.g. with tsmuxer or ffmpeg), you will notice the video stream will be the same size for both (despite what mediainfo says - it only reads the header, and not accurate for many things) . ie. the extra size is just in the container . It's likely the Sony values are different than the ones used by ffmpeg



Is the delay real ? Note mediainfo misreports many things, and 17ms is hardly perceptible

for the delay, you can use -itsoffset in ffmpeg, but I think it only works on video relative to audio. And it might be different for each file

‘-itsoffset offset (input)’ Set the input time offset in seconds. [-]hh:mm:ss[.xxx] syntax is also supported. The offset is added to the timestamps of the input files. Specifying a positive offset means that the corresponding streams are delayed by offset seconds.

[wwaag]

Using some test files in Vegas and viewing their waveforms, I confirmed that there is a 10 msec. delay being introduced during muxing which is the same value that encoders such as Main Concept and Procoder also introduce. Using the itsoffset command for the ac3 file, I was able to correct for the delay so that the waveforms of the original and remuxed files are the same. I'm happy!

Here is the command line:

for %a in ("*.m2ts") do ffmpeg -i "%~na.m2ts" -itsoffset 00:00:00.010 -i "%~na.ac3" -c copy -map 0:0 -map 1:0 "%~na.new.m2ts"

One final question. Can the wav to ac3 command line be incorporated into the batch remux command line? I'm sure it can, but I'm not quite sure how to proceed. Thanks so much.

wwaag

[poisondeathray]

Can the wav to ac3 command line be incorporated into the batch remux command line?

separate the 2 commands by "&&" (without the quotes) for sequential processing (1st command is executed before the 2nd), or use a batch file

[wwaag]

One additional question. Is there a way to also include a PGS text stream in addition to the video and audio? Thanks.