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All-purpose convertors

Biswajit.HD

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It is important to have the right playback format if you want to enjoy your movies and music.
The term 'multimedia' used to mean only MP3s for music and DVDs for movies. However, today, even experienced users find it difficult to grasp the various standards that exist. If you want to convert a movie or even music for a particular device, you will need to know its supported audio and video formats in addition to its resolution and maximum bit rate. You shouldn't have to study them to achieve the best possible image quality. You can instead use a program that sets all options and converts your files at the click of a button.

Formats

We tested eight programs, which will help you convert all possible multimedia files, from MP3s to Blu-ray movies. The subjects are divided into free and commercial products.

With the exception of Tunebite, all tools failed to work with disks that had any sort of copy protection, most notably DVDs. As far as audio is concerned, almost all tools could play popular formats such as AAC, MP3 and WMA, which are supported by iPod, cell phones, and other popular devices. Only AVS Video Converter limited itself to AAC. Formats such as FLAC, WavPack and Monkey Audio are more for audiophiles, who look for nothing but the best in quality, but are good to have available. Free tools such as MediaCoder and SUPER are the only ones which offer Dolby AC3 as well as the efficient HE-AAC compression format.

For now, only the free converters offer output of all important containers of Blu-ray (M2TS) via MPG, AVI, MP4 and Matroska (MKV) up to Flash (FLV). The commercial competitors generally do not support Matroska, which is not often found in standalone devices. Except for the AVS Converter and Movavi, which has many drawbacks, none of the other tools offer conversion to Blu-ray format (M2TS).

Profile

The commercial products concentrate on standards such as AVI, which is basically used for the DivX Home Theater profile for playing MPEG4 films on a DVD player. MP4 is used more extensively to make high resolution movies; these are specifically aimed towards devices like the PlayStation 3 (PS3). However, videos can also be converted to smaller resolutions to support playback on smartphones. All the products provide suitable profiles for these devices. All converters came with an iPhone profile, which is not surprising. But if you want to convert videos for lesser-known cell phones, you do not have much of a choice. Relatively good commercial products such as Movavi have profiles for all big manufacturers, from Samsung to Nokia, but only the free XMedia Recode supports the Android G1.

There are a handful of converters, like S.A.D, which do not work thoroughly. The tool restricts the resolution for the iPhone to 480x320, the maximum possible resolution being 640x480. For the PSP, it offers just 320x240, whereas the latest PSP offers a resolution of 480x272. Another strange finding is the inclusion of an MPEG4 encoder used in the Tunebite iPhone profile, even though H.264 is available and offers much better quality at low bit rates. The only tool missing in Tunebite is an MPEG2 encoder.

Several converters believe “It should just work”, and end up overlooking important compression technologies such as B-Frames. The only programs that use B-Frames are SUPER and commercial products.

When converting to DivX, most of the free options made use of the open source Xvid container. Unfortunately, to allow compatibility on older DVD players, the Home Theater profile doesn’t make use of B-Frames. These shortcomings were detected using an analysis tool called MediaInfo. You therefore need to tweak the required profile manually.

It is quite annoying if the converter does not stick to the set bit rate. In our test clips, all converters were set to 900 Kb/s with the output format set to AVI. Movavi managed just 830 Kb/s. The results were even worse for MPEG2. In this case, SUPER converted the clip at 1.9 MB/s instead of the set 3 MB/s. This resulted in us not being able to specify the desired file size of the converted film in any converter. Instead, the most you could do was access the bit rate since some programs allow you to specify the expected size of the video.

In spite of these difficulties, the converters are not very different when it came to image quality. This is because x264 as well as Xvid use the H.264 and MPEG4 encoders and MPEG2 uses MEncoder or FFmpeg to encode. Having said that, x264 and Xvid deliver quality which outdoes commercial competitors.

Quality

It is eventually for you to decide whether the conversion is to your liking or not. In addition to a subjective image impression, we used the PSNR value (Peak Signal to Noise Ratio) as well as the SSIM (Structural Similarity) for quality assessment. Both measure the difference between the original and converted films frame by frame.

Altogether, FormatFactory earns the maximum points in comparison to the test winner MediaCoder. Both programs as well as XMedia Recode convert the HD trailer of “Wolfman” optimally into H.246 at 3 MBit/s. You can hardly notice any difference when compared to the DivX profile used for DVD players. The main reason FormatFactory delivers the best image is because it uses B-frames in addition to the latest version of Xvid.

In the overall roundup, the commercial programs do a rather bad job since they use their own MPEG4 encoders rather than Xvid. The poor PSNR and SSIM values of QuickConvert have less to do with the encoder than with the maximum resolution of 640x480. We had to upscale the picture first to carry out the measurement. We converted a DVD trailer at 3 MBit/s for the MPEG2 measurement. The level of the programs was much better here, though not excellent. This could be because many free tools support multipass, i.e. conversion in several steps, but this is not activated in the preset profiles.

If you look at the charts carefully, even our test winner could not fulfil all requirements. MediaCoder is easily one of the fastest converters, mainly due to the fact that it is the only one that supports 64-bit processing. In addition to the x264 encoder, it also uses CUDA, which employs the resources of a graphics card. However, a few important profiles are missing and it thus cannot be used universally. XMedia Recode manages to strike a fine balance between versatility and simplicity with pre-defined profiles, plus access to all encoder settings for experts. Unfortunately, it is very slow and therefore not at the top of the table.


Verdict

The converters essentially swung between simple usage and optimum results. The free MediaCoder not only has a decent set of encoders and predefined profiles, but also gives you complete access to all settings. Sadly, commercial competitors rely on a simple interface and compromise on configurability.


Source : Chip Magazine.
 
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