Hi Users,
I am trying to write some software that uses the ffv1 encoder, however I am
unable to produce a valid file using the c api.
I have had success with libx264 and lib264rgb encoders.
I have attached original.c which is a modified version of the example found at
https://ffmpeg.org/doxygen/trunk/encode_video_8c-example.html
All that is changed is the pixel format to GRAY16 and the population of the
frame data.
to run it I do:
./original "gray.mkv" "ffv1" to load the ffv1 encoder and output a mkv file.
I have attached the output which shows the encoder running and the output from
ffplay trying to play the file.
The return code from avcodec_recieve_packet() is always AVERROR(EAGAIN).
Is someone able to modify the example code such that it works for ffv1 or tell
me what I'm mising?
Thanks,
James
/*
* Copyright (c) 2001 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/**
* @file libavcodec encoding video API usage example
* @example encode_video.c
*
* Generate synthetic video data and encode it to an output file.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libavcodec/avcodec.h>
#include <libavutil/opt.h>
#include <libavutil/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 <output file> <codec name>\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;
c->pix_fmt = AV_PIX_FMT_GRAY16;
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, 0);
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.
On the first round, the frame is fresh from av_frame_get_buffer()
and therefore we know it is writable.
But on the next rounds, encode() will have called
avcodec_send_frame(), and the codec may have kept a reference to
the frame in its internal structures, that makes the frame
unwritable.
av_frame_make_writable() checks that and allocates a new buffer
for the frame only if necessary.
*/
ret = av_frame_make_writable(frame);
if (ret < 0)
exit(1);
/* Prepare a dummy image.
In real code, this is where you would have your own logic for
filling the frame. FFmpeg does not care what you put in the
frame.
*/
for (y = 0; y < c->height; y++) {
for (x = 0; x < c->width; x++) {
frame->data[0][y * frame->linesize[0] + x] = 250;
}
}
/* 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.
It makes only sense because this tiny examples writes packets
directly. This is called "elementary stream" and only works for some
codecs. To create a valid file, you usually need to write packets
into a proper file format or protocol; see mux.c.
*/
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;
}
⯠./original "gray.mkv" "ffv1"
[ffv1 @ 0x8f9700] bits_per_raw_sample > 8, forcing range coder
Send frame 0
Write packet 0 (size= 1210)
Send frame 1
Write packet 1 (size= 1036)
Send frame 2
Write packet 2 (size= 1035)
Send frame 3
Write packet 3 (size= 1035)
Send frame 4
Write packet 4 (size= 1034)
Send frame 5
Write packet 5 (size= 1034)
Send frame 6
Write packet 6 (size= 1034)
Send frame 7
Write packet 7 (size= 1033)
Send frame 8
Write packet 8 (size= 1033)
Send frame 9
Write packet 9 (size= 1033)
Send frame 10
Write packet 10 (size= 1210)
Send frame 11
Write packet 11 (size= 1036)
Send frame 12
Write packet 12 (size= 1035)
Send frame 13
Write packet 13 (size= 1035)
Send frame 14
Write packet 14 (size= 1034)
Send frame 15
Write packet 15 (size= 1034)
Send frame 16
Write packet 16 (size= 1034)
Send frame 17
Write packet 17 (size= 1033)
Send frame 18
Write packet 18 (size= 1033)
Send frame 19
Write packet 19 (size= 1033)
Send frame 20
Write packet 20 (size= 1210)
Send frame 21
Write packet 21 (size= 1036)
Send frame 22
Write packet 22 (size= 1035)
Send frame 23
Write packet 23 (size= 1035)
Send frame 24
Write packet 24 (size= 1034)
////////////////////////////////////////
⯠ffplay gray.mkv
ffplay version 4.4.3 Copyright (c) 2003-2022 the FFmpeg developers
built with gcc 11 (GCC)
configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg
--docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64
--mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -flto=auto
-ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
--extra-ldflags='-Wl,-z,relro -Wl,--as-needed -Wl,-z,now
-specs=/usr/lib/rpm/redhat/redhat-hardened-ld
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 ' --extra-cflags='
-I/usr/include/rav1e' --enable-libopencore-amrnb --enable-libopencore-amrwb
--enable-libvo-amrwbenc --enable-version3 --enable-bzlib --enable-chromaprint
--disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt
--enable-gnutls --enable-ladspa --enable-libaom --enable-libdav1d
--enable-libass --enable-libbluray --enable-libbs2b --enable-libcdio
--enable-libdrm --enable-libjack --enable-libfreetype --enable-libfribidi
--enable-libgsm --enable-libilbc --enable-libmp3lame --enable-libmysofa
--enable-nvenc --enable-openal --enable-opencl --enable-opengl
--enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse
--enable-librsvg --enable-librav1e --enable-librtmp --enable-librubberband
--enable-libsmbclient --enable-version3 --enable-libsnappy --enable-libsoxr
--enable-libspeex --enable-libsrt --enable-libssh --enable-libsvtav1
--enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libv4l2
--enable-libvidstab --enable-libvmaf --enable-version3 --enable-vapoursynth
--enable-libvpx --enable-vulkan --enable-libglslang --enable-libwebp
--enable-libx264 --enable-libx265 --enable-libxvid --enable-libxml2
--enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2
--enable-avfilter --enable-avresample --enable-libmodplug --enable-postproc
--enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug
--disable-stripping --shlibdir=/usr/lib64 --enable-lto --enable-libmfx
--enable-runtime-cpudetect
libavutil 56. 70.100 / 56. 70.100
libavcodec 58.134.100 / 58.134.100
libavformat 58. 76.100 / 58. 76.100
libavdevice 58. 13.100 / 58. 13.100
libavfilter 7.110.100 / 7.110.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 9.100 / 5. 9.100
libswresample 3. 9.100 / 3. 9.100
libpostproc 55. 9.100 / 55. 9.100
[matroska,webm @ 0x7f9c44000c80] Format matroska,webm detected only with low
score of 1, misdetection possible!
Truncating packet of size 1531168 to 26380
[matroska,webm @ 0x7f9c44000c80] EBML header parsing failed
gray.mkv: Invalid data found when processing input
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