If you mean a prerecorded bhajan MP4 that you plan to upload or loop, reduce its size by re-encoding a copy and checking the result. If you mean the feed going to YouTube while you are live, configure the encoder’s live resolution, frame rate and bitrate instead; compressing an existing file is a different task.
There is no single CRF value or preset that guarantees a suitable size and sound for every bhajan recording. Start from the source file, decide what quality loss you can accept, and compare an actual sample before committing to a full encode.
Choose the workflow: file or live feed
An MP4 is a container, not a streaming setting. It can contain video and audio tracks encoded in different formats, at different resolutions and bitrates. Re-encoding changes the stored media and can reduce its file size, but the result depends on what is in the source and on the choices you make.
A live encoder, by contrast, produces a feed continuously and sends it to YouTube. Its bitrate affects the data sent per second, not the size of an MP4 already on your drive. For a live broadcast, use the YouTube live-ingestion recommendations for your chosen resolution, frame rate and codec rather than copying figures from upload guidance.
Ask yourself what needs changing. If the file takes too long to upload, uses too much storage, or is awkward to handle, re-encoding may help. If a live stream stutters or cannot keep up with its connection, inspect the live encoder and available upload capacity. Reducing the MP4 file size alone will not fix an unstable live feed.
This distinction matters for a 24/7 channel. You might prepare a long loop as a file, or you might play that file through an encoder on a computer. The first step is the same—understand the file—but the settings that govern a prepared MP4 are not automatically the settings that govern YouTube ingestion. For background on what a continuous loop can use over time, see how much data a 24/7 YouTube live video loop uses in India.
Check the source before changing it
Keep an untouched copy of the original. Before encoding, note the resolution, frame rate, duration, video codec, audio codec and current file size. A media information tool can show these details; if you use a command-line tool, inspect the file first rather than assuming its name or extension tells you what is inside.
Listen to a representative part as well as watching it. A bhajan recording may have a steady devotional image, but the audio can contain details that matter: a lead vocal, chorus, harmonium, tabla, cymbals, room reverberation or a quiet introduction. A setting that looks acceptable on a still image can make a voice sound rough or soften a rhythmic instrument. Your quality judgement should include both picture and sound.
Check whether there is genuine motion or fine detail. A static image with a small amount of animation can respond differently to compression from footage of a singer, a temple procession, flickering lamps or moving text. Small lettering and thin decorative lines may show blocking before a broad background does. That does not establish one ideal setting; it tells you what to inspect in your own material.
Write down the constraints before encoding: where you will store the result, whether upload time is a concern, how much encoding time you can wait for, and what visual or audio changes would be unacceptable. A smaller output is not automatically a better output if it damages the words on screen or the sound people have come to hear. For a long-running channel, the guide to turning old YouTube videos into a 24/7 live stream may help you think through the file-to-broadcast path as a whole.
Choose an MP4 video and audio format
For a normal YouTube upload file, YouTube’s recommended upload encoding settings describe MP4 with H.264 video and audio options that include AAC-LC. Follow the current upload guidance when preparing an upload. An .mp4 extension by itself does not show whether the tracks use those formats or whether the encode will meet your quality needs.
The container, video codec and audio codec do different jobs. MP4 holds the tracks and related metadata. H.264 describes how the video is compressed. AAC is one audio format. Changing a codec or bitrate can affect compatibility, file size and quality; putting the same encoded tracks in a different container does not necessarily make them smaller.
For a source that already has suitable audio, avoid re-encoding it unnecessarily if your tool and workflow allow you to copy the audio track into the output. Re-encoding can change sound quality, while leaving it untouched can preserve a suitable track. If you need to re-encode audio, choose the format and bitrate for your listening needs and compare a vocal passage and an instrumental passage after the encode.
YouTube also advises placing MP4 metadata at the beginning of the file for upload. In FFmpeg, -movflags +faststart moves the moov metadata atom forward. This can help playback behaviour while a file is being read; it is not a compression setting and does not reduce the file’s encoded video or audio data. The FFmpeg documentation explains the option.
YouTube publishes upload bitrate references by resolution and frame rate, including SDR examples such as 1080p at 8 Mbps, 720p at 5 Mbps and 480p at 2.5 Mbps. These are YouTube upload recommendations from undated help guidance, not a measured optimum for a Hindi bhajan and not live-ingestion targets. Use the current upload table as platform guidance, then judge whether the result is suitable for your source and purpose.
Re-encode for quality, then compare size
A quality-based re-encode lets you specify a visual quality target rather than directly demanding an exact output size. With FFmpeg’s libx264 encoder, the CRF control is used for this purpose. Lower CRF values generally retain more quality and create larger files, while higher values generally trade some quality for a smaller file. The relationship is not a promise of a particular size: content, duration, frame size, motion and encoder settings all matter.
The preset controls the encoder’s search effort and speed, not a fixed quality level. A slower preset can take longer to encode while seeking a more efficient result at a given quality setting. If overnight processing is acceptable, a slower preset may be worth comparing; if you need a quick turnaround, a faster one may suit the job. Check the resulting file rather than assuming the preset name predicts its size or quality.
Here is an illustrative command structure:
ffmpeg -i input.mp4 -c:v libx264 -preset slow -crf 23 -c:a aac -b:a 192k -movflags +faststart output.mp4
The CRF and audio bitrate in this example are starting values for demonstrating the command’s structure, not a tested bhajan recommendation or guaranteed outcome. Choose them in light of your source and acceptable quality loss. If the original audio is already suitable, consider preserving it rather than re-encoding it; confirm your tool’s options and check the output.
For a fair comparison, make one change at a time. Keep a note of the source and output sizes, CRF, preset, audio choice and encoding time. Then compare the sample on the same screen and speakers, at the size people are likely to watch. If a setting causes visible damage or unpleasant sound, adjust it and encode another sample before processing the full-length file.
You can instead target a bitrate when you have a file-size ceiling or a delivery constraint. But a bitrate target alone does not ensure that every part of a varied video will look equally good. A quiet image may need less data than moving footage, and a very low target can become noticeable during motion or in fine detail. Quality-based and bitrate-based workflows answer different questions: one asks what quality setting to use, the other asks how much data to allocate. Choose based on your actual constraint.
Keep the source frame rate
Do not lower the frame rate merely to make the file smaller. YouTube says, “Content should be encoded and uploaded in the same frame rate it was recorded.” Check the source first and preserve its frame rate through the upload encode unless you have a specific production reason to change it.
Changing frame rate can alter motion and timing, and it is not a substitute for a considered quality or bitrate choice. A devotional still image may appear unchanged at first glance, but a source with camera movement, a singer’s gestures, flame movement or scrolling lyrics can reveal uneven motion after conversion. Keep the source frame rate as the baseline, then compare other changes separately if you have a reason to test them.
Resolution is another independent choice. Reducing resolution may reduce the amount of video data required, but it can make lyrics, artwork and facial details less legible. Do not downscale only because a smaller file sounds convenient; view the output at its likely playback size and check the smallest important text. YouTube’s upload table is a reference for supported upload settings, not evidence that a particular resolution is best for every channel.
Check the result before uploading
Compare the output file’s actual size with the original and confirm that the encode completed without errors. A quality-based encode cannot promise a file size in advance, so use the result to decide whether it meets your storage or upload constraint. If not, return to the source and make a deliberate adjustment rather than repeatedly changing several controls at once.
Watch the start, middle and end, and include passages that represent the hardest material: moving imagery, small text, dark areas, bright lamps, or quick visual changes. Listen to the vocal and instrumental sections. Check that the audio has not been clipped, muted, desynchronised or made harsh. A short representative test is a practical way to avoid waiting for a full encode only to discover an issue; it is a workflow suggestion, not a test result for a particular bhajan file.
Keep a simple comparison record. For example, note “source”, “sample A” and “sample B”, then list file size, frame size, frame rate, video setting, audio setting, encode duration and your observations. This makes it easier to identify which change helped. The guide to looping multiple videos in OBS without a transition gap is relevant if the file will become one part of a playlist; check both the encoded clips and the transitions in the actual playback workflow.
Before upload, confirm the output opens and plays from beginning to end. If the MP4 is intended for upload, use the current YouTube upload encoding guidance, including its container and codec recommendations. Fast-start metadata can improve how a file begins playback in some workflows, but it does not make a damaged encode good or reduce the encoded file size.
Use separate settings for a live encoder
If you are sending a live feed to YouTube, do not use upload bitrate references as though they were ingestion instructions. YouTube publishes separate live encoder settings, with recommendations that vary by codec, resolution and frame rate. Find the row matching your intended output, and configure the encoder accordingly.
For RTMP or RTMPS, YouTube’s live guidance recommends constant bitrate (CBR) and a two-second keyframe interval. These are live encoder recommendations, not settings for shrinking a prerecorded MP4. The connection sending the feed must also be able to sustain the selected stream; if it cannot, a lower live output setting may be more practical than repeatedly changing the source file.
For a live loop running from a local computer, keep the two stages distinct: the media player supplies the file, and the encoder sends a live feed. A pre-encoded file may be easier to store or upload, but the live encoder still needs a valid feed configuration. If the computer or connection is the source of interruptions, file compression will not resolve that operational problem. This guide to scheduling a YouTube livestream playlist for Indian national holidays covers a related planning task, while the live settings page remains the place to verify ingestion values.
If keeping a computer running and recovering a broadcast after a drop is the specific burden, StreamNeo removes that particular operational task by letting you upload a video and run it as a 24/7 YouTube live stream without keeping your own computer on. That does not choose the right compression for your source, guarantee a particular quality, or replace checking YouTube’s current requirements.
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
Will compressing my MP4 lower the bitrate of my live stream?
Not by itself. Re-encoding changes the stored file; a live encoder’s output bitrate is configured separately. If the live feed has trouble, check its encoder settings and sending connection.
What CRF should I use for a Hindi bhajan video?
There is no source-specific value established here that suits every bhajan. Try a short representative section, inspect the picture and listen to the audio, then adjust one setting at a time against your own quality and size requirements.
Will +faststart make the MP4 smaller?
No. It moves MP4 metadata towards the beginning of the file to help playback behaviour in relevant workflows. It does not reduce the amount of encoded video or audio data.
Should I reduce the frame rate to save space?
Keep the source frame rate for upload unless you have a specific reason to change it. YouTube’s upload guidance says to encode and upload at the same frame rate as recorded; test any deliberate change for motion and timing before using it for the full video.