You can make an MP4 smaller without changing its pixel dimensions by re-encoding it at a lower bitrate or, where your playback chain supports it, with a more efficient codec. Either approach changes the encoded video, so you need to compare the result: retaining width and height does not mean retaining every detail or motion quality.
A smaller file is easier to store and move, but it does not by itself make a 24/7 YouTube broadcast more reliable. File compression, upload capacity, playback, and recovery from a dropped stream are separate matters. The useful workflow is to keep the dimensions fixed, test a short representative section, check the output against YouTube’s current ingest guidance, and then test the actual live setup.
What unchanged resolution does—and does not—mean
Resolution is the frame’s pixel dimensions: for example, a source file might be 1920 pixels wide by 1080 pixels high. Keeping resolution unchanged means that the encoded output still has those same dimensions. It does not specify how much information is used to describe each frame, how smoothly motion is represented, or how faithfully colour and fine texture survive compression.
Bitrate is a different control. It describes the amount of encoded data used over time. When you reduce video bitrate while leaving width, height, frame rate, and duration alone, the output can use fewer bits and take up less space. The encoder has less data to represent the picture, however, and may discard detail or make compression artefacts more visible.
Those effects depend on the footage and the encoder settings. A static temple image with a slow fade may tolerate a lower bitrate than a scene with moving leaves, flowing water, camera movement, or fine text. A bhajan video with a still background and changing lyrics has different demands from a local news loop with scrolling headlines. Pixel dimensions alone cannot tell you whether a given encode will look acceptable.
Before changing anything, record the source dimensions, frame rate, duration, audio format, and current bitrate. Then make the output dimensions exactly match the source. Do not select an option that resizes to a smaller preset or crops the frame. The task is to change compression, not resolution or composition.
It is also worth separating “same resolution” from “no visible loss”. Re-encoding at a lower bitrate can soften texture, block detail in movement, or create banding in smooth gradients even at the same dimensions. If those changes are noticeable in the places viewers are likely to watch, use a less aggressive encode or keep the original file.
Lower bitrate: the direct size control
For a fixed duration, bitrate is the most direct way to estimate file size. If you lower the video bitrate, the encoded video generally needs fewer bits. The trade-off is that the encoder must represent the same number of pixels with a smaller data budget, and quality can decline. There is no single bitrate that suits every 1080p file or every kind of channel.
Begin by checking the current YouTube guidance for the resolution, frame rate, and codec you intend to send. YouTube’s live encoder settings and bitrate guidance gives recommendations that vary with those choices. Treat its current table as the reference for stream ingestion rather than relying on a universal number copied from an old preset or a video forum. Regional versions and account contexts can show different tables, so confirm the relevant current page before settling on an output target.
YouTube lists constant bitrate encoding in its encoder guidance and recommends a two-second keyframe interval, not exceeding four seconds. The guidance also lists supported video and audio formats and a maximum frame rate of up to 60 fps. These are stream configuration requirements and recommendations, not proof that a particular compressed file will look good. Check the current official page for the exact settings that apply to your stream.
A practical approach is to make a test encode at a modestly lower bitrate than the source and compare it on a screen similar to the one your audience uses. If it looks clean, test a further reduction; if artefacts become obvious, step back. Do not chase the lowest possible number. For a devotional station with a largely still image, legibility of lyrics and edges may matter most. For ambient footage, gradients and slow movement may reveal problems that a still frame hides.
Remember that the outgoing live stream has its own bitrate. A smaller stored MP4 does not automatically mean YouTube receives a smaller live bitrate: playback or encoder software may re-encode the file at a separate setting. Conversely, if a workflow sends the file’s encoded video through without re-encoding, its file bitrate may inform the outgoing load. Confirm how your actual playback and streaming setup handles the file before assuming one bitrate controls both.
For a broader discussion of what to set on the broadcast side, see the 24/7 YouTube stream bitrate guide. It addresses stream output, which is related to but not interchangeable with the bitrate used to make an MP4.
A more efficient codec needs a compatibility check
A codec is the method used to compress and reconstruct video. A newer or more efficient codec may reach a similar visual result at fewer bits in some circumstances, but the result depends on the encoder, content, bitrate, and quality target. Changing the codec name alone does not guarantee a smaller file. If the new encode uses a higher bitrate, for example, it may be larger.
Compatibility is the main practical constraint. The codec must work all the way through your playback software, any encoder or relay you use, and YouTube’s live ingest path. YouTube’s current encoder page lists H.264, H.265 (HEVC), and AV1 among supported video codecs, but support in one part of the chain does not prove that every local player, operating system, or streaming configuration can handle it. Check the actual software documentation and run a test stream before relying on a less familiar format overnight.
There may also be a processing trade-off. A more demanding encode can take longer to produce, and decoding can require more of the playback device than a familiar codec. The available evidence here does not establish a comparative CPU ranking for your machine or footage. Test your own file on the actual playback device, especially if you are using a modest computer or an older setup.
Audio is separate from video compression. If the channel carries music, chanting, speech, or ambient sound, listen to the output as well as inspecting the picture. YouTube’s current encoder guidance recommends 128 Kbps for stereo audio, but check the live page for current settings and choose audio settings that preserve the sound your programme needs. Do not reduce the audio merely to achieve a smaller video file if the channel depends on clear music or voice.
If you are using OBS, its media source and output settings determine how the content is handled in that workflow. The OBS settings for a looping store promo video offer a useful reference for the playback side, though you should still verify the settings for your own codec and stream. A codec experiment is worth keeping only if the whole chain plays it reliably and the picture and sound remain suitable.
Estimate file size from bitrate and duration
You can estimate the encoded file size from the combined audio and video bitrates and the duration. Use bits per second for both bitrates and seconds for duration:
approximate bytes = (video bitrate + audio bitrate) × duration ÷ 8
The division by eight converts bits to bytes. The result is approximate because the MP4 container and other stream data add some overhead, and actual variable-bitrate encodes can vary across sections. Treat the calculation as a planning estimate, not as a promise about the final file or its visual quality.
For a simple example, suppose a one-hour file has a combined average bitrate of 2,000,000 bits per second. Multiply 2,000,000 by 3,600 seconds, then divide by eight; the estimate is 900,000,000 bytes before container overhead. This example illustrates the arithmetic only. It is not a recommended bitrate for any particular resolution, frame rate, codec, or programme.
When comparing two encodes of the same duration, the one with a lower combined bitrate will generally be smaller. Compare like with like: include audio in both calculations, and do not compare a video-only bitrate from one file with a total bitrate from another. If your editor reports an average bitrate and a peak bitrate, use the average for a rough size estimate and inspect the output file’s actual size after encoding.
The equation also helps you decide whether the effort is useful. If you need to move a long programme over a limited connection or have finite storage, a lower bitrate may reduce those demands. But if the source already meets your storage needs, the quality cost of re-encoding may outweigh the saving. Keep an unchanged copy of the source until you have reviewed the test and confirmed the new file works.
Do not infer the required live upload bandwidth from the MP4 file size alone. The live stream’s total outgoing bitrate, audio, other network traffic, and the way the player encodes or packages the content matter. YouTube’s streaming tips state that the total stream bitrate must fit within available upload bandwidth. Leave practical headroom rather than planning for a connection that only just matches the configured output.
Compare a short test encode, not just a setting
A short test can show whether the size saving is worth the visible change before you process a long programme. Choose a section that represents the file, rather than the first quiet seconds. Include the parts that are hardest to encode: motion, fine detail, text, gradients, or a change in lighting. If a devotional video has mostly a still image but animated lyrics, the test should include those lyrics moving or changing.
Create two or more versions from the same source section. Keep width, height, frame rate, and duration identical. Change one variable at a time: first bitrate, then codec if you have confirmed compatibility. If you change bitrate, codec, frame rate, and audio together, you will not know which change caused a visible defect or a playback problem.
Compare the files at the same playback size and, where possible, side by side. Look for softness around text, blockiness in moving areas, ringing around sharp edges, banding in skies or colour fades, and flicker or smearing during motion. Listen for changes to the programme audio. A paused frame is not enough: compression problems often become apparent only when the picture moves.
Write down the output size and settings for each test. Your notes might say that one version is smaller but makes white lyrics harder to read, while another is a little larger and preserves a slow gradient. This makes the decision specific to your content rather than an abstract question of which codec is “best”. A smaller file is useful only if it remains acceptable for the way viewers will use it.
Then test the chosen file in the actual playback-to-YouTube path. YouTube recommends testing before going live and checking stream health and error messages; see its live stream troubleshooting guidance. A local file that opens successfully is not enough to establish that the live encoder accepts it or that the outgoing stream matches the target settings. Make the test representative of your normal audio and movement, and check the platform’s current messages rather than assuming silence means everything is correct.
Check the file and the 24/7 setup separately
Before putting an encode into a long-running channel, confirm its pixel dimensions, duration, audio, codec, and playback from beginning to end. Check that the start and end behave as expected, that the loop does not leave an unwanted blank interval, and that the sound does not jump or cut out at the join. If you have a local archive or recording requirement, verify that separately too.
Next, check the live settings against YouTube’s current encoder guidance. Confirm the intended video codec, audio codec, frame rate, keyframe interval, and bitrate. YouTube recommends a two-second keyframe interval and says not to exceed four seconds; follow the current page for any other value rather than treating an MP4 export preset as the authority for your live output. A file can have the correct dimensions and still be unsuitable for the stream configuration.
Finally, test the operational path. A smaller MP4 can reduce storage use or transfer time, but it cannot keep a computer powered, restore a broken internet connection, restart a crashed playback process, or recover a failed broadcast by itself. Continuity depends on the playback and encoder software, the host, network conditions, power, and the way the setup recovers from errors. YouTube’s documentation does not guarantee continuous playback for a particular file.
If your existing workflow keeps a computer running all night, reduce the operational burden independently of file compression. For example, StreamNeo can remove the need to leave your own computer on for the file’s continuous YouTube broadcast, so the local machine is no longer the point of failure you are trying to keep awake. That does not change the need to prepare a suitable file, check the channel and stream settings, or verify the service against your requirements.
For a home-hosted arrangement, the home-server streaming guide is relevant to the separate questions of host and playback operation. If Windows updates are one of your known overnight risks, see how to stop updates interrupting an OBS stream. Those operational checks solve different problems from reducing the MP4’s bitrate.
Before committing, compare the operating options on the pricing page. When the file and channel are ready, start free — 24-hour trial, no card.
FAQ
Can I reduce an MP4’s size and keep the same resolution?
Yes. Re-encode it with the same width and height and reduce the bitrate, or test a more efficient codec that your playback and streaming chain supports. The dimensions stay the same, but lower data use can reduce visible quality, so review a representative encode before replacing the source.
What bitrate should I use for a 24/7 YouTube stream?
There is no universal bitrate for every video. YouTube’s current recommendations depend on codec, resolution, and frame rate, so check its live encoder table for your intended configuration. Also confirm that the total outgoing bitrate fits your available upload bandwidth.
Will a smaller MP4 make the stream run without interruption?
No. A smaller file may be easier to store or transfer, but it does not guarantee a stable broadcast. Playback, host power, network capacity, encoder behaviour, and recovery from failures all affect continuity, so test those parts separately.
Should I change codec instead of lowering bitrate?
Only if the entire playback-to-ingest path supports the codec and a test shows an acceptable result. Codec changes can affect compatibility and processing demands, and do not guarantee a smaller file by themselves. Compare size, visible detail, audio, and actual stream behaviour before choosing.