Newest 'libx264' Questions - Stack Overflow

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  • Access to motion vector's (x, y) coordinate while using libx264 encoder

    8 mars 2022, par Rockland

    I want to know if it is possible to get motion vectors values (x, y) somehwhere in the enconding process while using libx264 encoder.

    I have a project where I need to modify motion vectors values during encoding process. What I want to do concretly is for exemple : motion_x = motion_x + 1 and/or motion_y = motion_y -1

    I want to know if it is possible to get motion vectors values (x, y) somehwhere in the enconding process while using libx264 encoder.

    I have a project where I need to modify motion vectors values during encoding process. What I want to do concretly is for exemple : motion_x = motion_x + 1 and/or motion_y = motion_y -1

    I know that it is possible to do that while using the standards ffmpeg encoders. Precisily in the function static int encode_picture(MpegEncContext *s, int picture_number) in the file mpegvideo_enc.c located in the ffmpeg's libavcodec directory, we can get and modify motion vector's values in the struct MpegEncContext (->current_picture.motion_val). When I use libx264 encoder, this function is not called so I don't know where and how to do that.

    Your help will be verry appreciated.

  • FFMPEG : Convert WebM VP8/VP9 multi-resolution video to MP4 (H.264)

    28 janvier 2022, par thedeadalive

    I have been trying to convert a multi-resolution WebM video ( VP9/VP8/H.264 ) (1280 x 1080 till the half, thereafter 1080 x 1280) to MP4 container with H.264 encoding for video.

    When transcoded with FFMPEG is locking into the frame size it's encountering at the start of the video (1280 x 1080 in this case) when transcoded with libvpx (for VP8 and VP9) and libx264 (for H264).

    The only instance i could get it right was when the Input WebM was having H.264 video and opus Audio, and ffmpeg was instructed to just copy the video stream and trans-code the Audio to aac only.

    Is there way in make ffmpeg support multi-resolution video transcoding?

    How to generate a sample video: On a Chrome or Firefox (on a device that supports auto rotation and has different resolution on portrait and landscape) that supports mediaRecorder API goto this link: https://webrtc.github.io/samples/src/content/getusermedia/record/ , start recording a video , while recording the video, change orientation, stop recording and download the video. file)

    Discussion Reference: https://groups.google.com/a/webmproject.org/forum/#!topic/webm-discuss/IgumDyMAHY0

  • Getting Error message Unknown encoder 'libx264' , any help appreciated

    16 janvier 2022, par Alex.Foster

    I am trying to compress videos files to a target size within python using ffmpeg-python for an A level project as part of my coursework, I keep getting this error saying it doesn't know the encoder. Not sure what I'm meant to do as this is literally an entirely new space to me. Am I meant to have installed the codec or something, or is there an alternative I can use?

    import os, ffmpeg
##import section:this part is where I import all of the modules I will use
import  tkinter
import shutil
from tkinter import filedialog
import os


def fileSelect():                                                                           #start of fileSelect function
    global startingLocation                                                                 #declares startingLocation as global variable
    global originalName                                                                     #declares originalName as global variable
    global fileType                                                                         #declares fileType as global variable
    startingLocation = filedialog.askopenfilename(initialdir="/", title="Select file",      #tkinter function that opens file explorer, lets user select file saves the file path as a variable
                    filetypes=(("video files", "*.mp4"),("images", "*.jpg*")))
    originalName = os.path.basename(startingLocation)                                       #os function that gets the actaul file name from the path string
    print (originalName)                                                                    #print statement to check if originalName has been found
    fileType = startingLocation.split('.')                                                  #splits original name where any full stop in found and saves array as variable
    fileType = fileType[-1]                                                                 #changes variable to have the str value of the final item in the array; the file type
    fileType = '.' + fileType                                                               #adds fullstop to the start of the file type so i dont have to repeatedly do it
    print (fileType)                                                                        #print statement to check file type is found correctly

def outputSelect():                                                                         #start of outputSelect function
     global outputLocation                                                                  #declares outputLocation as global variable
     outputLocation = filedialog.askdirectory(initialdir="/", title="Select folder")        #tkinter function that opens file explorer, lets the user select of folder as saves the folder path as a variable

def fileNewName():                                                                          #start of fileNewName function
    global customName                                                                       #declares customName as global variable
    customName = input("Enter the end name of your file")                                   #simple code assigning user input to the custom name vairable
    customName = customName + fileType                                                      #add the fileType onto the end of the custom name

def compress():                                                                             #start of compress function
    fileSelect()                                                                            #calls the fileSelect function
    outputSelect()                                                                          #calls the outputSelect function
    fileNewName()
    global src
    global dst                                                                           #calls the fileNewName function
    src = startingLocation                                                                  #assigns startingLocation str as src, so the shutil module is able to use it in a cleaner way
    dst = outputLocation                                                                    #assigns outputLocation dst as src, so the shutil module is able to use it in a cleaner way
    shutil.copy(src, dst)                                                                   #shutil command that copies the file from src to dst
    src = outputLocation + '/' + originalName                                               #reassigns src as the location of the file copy
    dst = outputLocation + '/' + customName                                                 #reassigns dst as the location of the file copy but with a new name
    shutil.move(src,dst)


def compress_video(video_full_path, output_file_name, target_size):
    # Reference: https://en.wikipedia.org/wiki/Bit_rate#Encoding_bit_rate
    min_audio_bitrate = 32000
    max_audio_bitrate = 256000

    probe = ffmpeg.probe(video_full_path)
    # Video duration, in s.
    duration = float(probe['format']['duration'])
    # Audio bitrate, in bps.
    audio_bitrate = float(next((s for s in probe['streams'] if s['codec_type'] == 'audio'), None)['bit_rate'])
    # Target total bitrate, in bps.
    target_total_bitrate = (target_size * 1024 * 8) / (1.073741824 * duration)

    # Target audio bitrate, in bps
    if 10 * audio_bitrate > target_total_bitrate:
        audio_bitrate = target_total_bitrate / 10
        if audio_bitrate < min_audio_bitrate < target_total_bitrate:
            audio_bitrate = min_audio_bitrate
        elif audio_bitrate > max_audio_bitrate:
            audio_bitrate = max_audio_bitrate
    # Target video bitrate, in bps.
    video_bitrate = target_total_bitrate - audio_bitrate

    i = ffmpeg.input(video_full_path)
    ffmpeg.output(i, os.devnull,
                  **{'c:v': 'libx264', 'b:v': video_bitrate, 'pass': 1, 'f': 'mp4'}
                  ).overwrite_output().run()
    ffmpeg.output(i, output_file_name,
                  **{'c:v': 'libx264', 'b:v': video_bitrate, 'pass': 2, 'c:a': 'aac', 'b:a': audio_bitrate}
                  ).overwrite_output().run()

compress()
compress_video(dst, outputLocation, 3 * 1000)

  • How to resolve "ERROR : libx264 not found" ?

    13 janvier 2022, par davidvarghese

    I needed to install ffmpeg with libx264 support for enabling H.264 encoding . I installed libx264 successfully using the below script with toolchains available in android-ndk-r9d .

     #!/bin/bash
 NDK=~/android-ndk-r9d
 SYSROOT=$NDK/platforms/android-8/arch-arm/
 TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64
 function build_one
 {
 ./configure \
 --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
 --sysroot="$SYSROOT" \
 --host=arm-linux \
 --enable-pic \
 --enable-shared \
 --disable-cli
 make clean
 make
 make install
 }
 build_one

    Now I wanted to build ffmpeg with libx264 support . I used the below script with --enable-libx264 , --enable-nonfree , --enable-gpl options as in the below script . 

    #!/bin/bash
NDK=~/android-ndk-r9d
SYSROOT=$NDK/platforms/android-8/arch-arm/
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64
function build_one
{
./configure \
--prefix=$PREFIX \
--enable-shared \
--enable-nonfree \
--enable-gpl \
--enable-libx264 \
--disable-doc \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffprobe \
--disable-ffserver \
--disable-avdevice \
--disable-doc \
--disable-symver \
--cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
--target-os=linux \
--arch=arm \
--enable-cross-compile \
--sysroot=$SYSROOT \
--extra-cflags="-Os -fpic $ADDI_CFLAGS" \
--extra-ldflags="$ADDI_LDFLAGS" \
$ADDITIONAL_CONFIGURE_FLAG
make clean
make
make install
}
CPU=arm
PREFIX=$(pwd)/android/$CPU
ADDI_CFLAGS="-marm"
build_one

    But when I run the script I'm getting error "ERROR: libx264 not found" .

    I suppose ffmpeg is not able to figure out the installed location of libx264 . After libx264 installation I have libx264.so file in /usr/local/lib executable at /usr/local/bin and header files at /usr/local/include directories .

    What all changes do I need to make to the ffmpeg build script in-order to make it detect libx264?

    Note : I am using Ubuntu 12.04(64 bit) for cross compiling .

  • How to get FFMPEG to encode H264 using libx264 ?

    12 décembre 2021, par Basit Anwer

    FFMPEG encode example fails to create a H264 video. MPEG1 works fine though.

    Pasting the code here as well

    
     * @file
     * video encoding with libavcodec API example
     *
     * @example encode_video.c
     */
    #include 
    #include 
    #include 
    #include avcodec.h>
    #include opt.h>
    #include imgutils.h>
    static void encode(AVCodecContext *enc_ctx, AVFrame *frame, AVPacket *pkt,
                       FILE *outfile)
    {
        int ret;
        /* send the frame to the encoder */
        if (frame)
            printf("Send frame %3"PRId64"\n", frame->pts);
        ret = avcodec_send_frame(enc_ctx, frame);
        if (ret < 0) {
            fprintf(stderr, "Error sending a frame for encoding\n");
            exit(1);
        }
        while (ret >= 0) {
            ret = avcodec_receive_packet(enc_ctx, pkt);
            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                return;
            else if (ret < 0) {
                fprintf(stderr, "Error during encoding\n");
                exit(1);
            }
            printf("Write packet %3"PRId64" (size=%5d)\n", pkt->pts, pkt->size);
            fwrite(pkt->data, 1, pkt->size, outfile);
            av_packet_unref(pkt);
        }
    }

    int main(int argc, char **argv)
    {
        const char *filename, *codec_name;
        const AVCodec *codec;
        AVCodecContext *c= NULL;
        int i, ret, x, y;
        FILE *f;
        AVFrame *frame;
        AVPacket *pkt;
        uint8_t endcode[] = { 0, 0, 1, 0xb7 };
        if (argc <= 2) {
            fprintf(stderr, "Usage: %s  \n", argv[0]);
            exit(0);
        }
        filename = argv[1];
        codec_name = argv[2];
        /* find the mpeg1video encoder */
        codec = avcodec_find_encoder_by_name(codec_name);
        if (!codec) {
            fprintf(stderr, "Codec '%s' not found\n", codec_name);
            exit(1);
        }
        c = avcodec_alloc_context3(codec);
        if (!c) {
            fprintf(stderr, "Could not allocate video codec context\n");
            exit(1);
        }
        pkt = av_packet_alloc();
        if (!pkt)
            exit(1);
        /* put sample parameters */
        c->bit_rate = 400000;
        /* resolution must be a multiple of two */
        c->width = 352;
        c->height = 288;
        /* frames per second */
        c->time_base = (AVRational){1, 25};
        c->framerate = (AVRational){25, 1};
        /* emit one intra frame every ten frames
         * check frame pict_type before passing frame
         * to encoder, if frame->pict_type is AV_PICTURE_TYPE_I
         * then gop_size is ignored and the output of encoder
         * will always be I frame irrespective to gop_size
         */
        c->gop_size = 10;
        c->max_b_frames = 1;
        c->pix_fmt = AV_PIX_FMT_YUV420P;
        if (codec->id == AV_CODEC_ID_H264)
            av_opt_set(c->priv_data, "preset", "slow", 0);
        /* open it */
        ret = avcodec_open2(c, codec, NULL);
        if (ret < 0) {
            fprintf(stderr, "Could not open codec: %s\n", av_err2str(ret));
            exit(1);
        }
        f = fopen(filename, "wb");
        if (!f) {
            fprintf(stderr, "Could not open %s\n", filename);
            exit(1);
        }
        frame = av_frame_alloc();
        if (!frame) {
            fprintf(stderr, "Could not allocate video frame\n");
            exit(1);
        }
        frame->format = c->pix_fmt;
        frame->width  = c->width;
        frame->height = c->height;
        ret = av_frame_get_buffer(frame, 32);
        if (ret < 0) {
            fprintf(stderr, "Could not allocate the video frame data\n");
            exit(1);
        }
        /* encode 1 second of video */
        for (i = 0; i < 25; i++) {
            fflush(stdout);
            /* make sure the frame data is writable */
            ret = av_frame_make_writable(frame);
            if (ret < 0)
                exit(1);
            /* prepare a dummy image */
            /* Y */
            for (y = 0; y < c->height; y++) {
                for (x = 0; x < c->width; x++) {
                    frame->data[0][y * frame->linesize[0] + x] = x + y + i * 3;
                }
            }
            /* Cb and Cr */
            for (y = 0; y < c->height/2; y++) {
                for (x = 0; x < c->width/2; x++) {
                    frame->data[1][y * frame->linesize[1] + x] = 128 + y + i * 2;
                    frame->data[2][y * frame->linesize[2] + x] = 64 + x + i * 5;
                }
            }
            frame->pts = i;
            /* encode the image */
            encode(c, frame, pkt, f);
        }
        /* flush the encoder */
        encode(c, NULL, pkt, f);
        /* add sequence end code to have a real MPEG file */
        if (codec->id == AV_CODEC_ID_MPEG1VIDEO || codec->id == AV_CODEC_ID_MPEG2VIDEO)
            fwrite(endcode, 1, sizeof(endcode), f);
        fclose(f);
        avcodec_free_context(&c);
        av_frame_free(&frame);
        av_packet_free(&pkt);
        return 0;
    }

    The code fails at encode call and every avcodec_receive_packet call returns AVERROR(EAGAIN)

    What am i missing here?

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